Journal of Sports Sciences
ISSN: 0264-0414 (Print) 1466-447X (Online) Journal homepage: http://www.tandfonline.com/loi/rjsp20
The relationship between lower-limb strength and match-related muscle damage in elite level professional European soccer players Adam Owen, Gordon Dunlop, Mehdi Rouissi, Moktar Chtara, Darren Paul, Hassane Zouhal & Del P. Wong To cite this article: Adam Owen, Gordon Dunlop, Mehdi Rouissi, Moktar Chtara, Darren Paul, Hassane Zouhal & Del P. Wong (2015) The relationship between lower-limb strength and match-related muscle damage in elite level professional European soccer players, Journal of Sports Sciences, 33:20, 2100-2105, DOI: 10.1080/02640414.2015.1064155 To link to this article: http://dx.doi.org/10.1080/02640414.2015.1064155
Published online: 09 Jul 2015.
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Date: 27 November 2016, At: 11:49
Journal of Sports Sciences, 2015 Vol. 33, No. 20, 2100–2105, http://dx.doi.org/10.1080/02640414.2015.1064155
The relationship between lower-limb strength and match-related muscle damage in elite level professional European soccer players
ADAM OWEN1,2, GORDON DUNLOP1, MEHDI ROUISSI3, MOKTAR CHTARA4, DARREN PAUL5, HASSANE ZOUHAL6 & DEL P. WONG7 1
Servette FC, Centre for Football Research, Geneva, Switzerland, 2Centre de Recherch et d’Innovation sur le Sport, Universite Claude Bernard Lyon.1, Lyon, France, 3CNMSS, El Menzah, Tunisia, 4CNMSS, Tunis, Tunisia, 5ASPETAR, Research dept, ASPETAR research in sport, Doha, Qatar, 6Universitie Rennes2, Sport Science, Avenue Charles Tillon, Rennes, France and 7Human Performance Laboratory, Technological and Higher Education Institute of Hong Kong, Hong Kong, China (Accepted 7 June 2015)
Abstract In professional soccer, the benefits of lower limb strength training have been advocated. However, from an aspect of performance development, specifically with respect to expression of fatigue and injury prevention, the advantages of increased lower body strength have received limited attention at the elite level of the game. The primary aim of this cross-sectional investigation was to examine the association between lower body strength and the expression of markers of fatigue as evaluated through muscle damage assessment following match play in professional soccer players. Ten male professional soccer players participated in this investigation (mean ± SD age 26.2 ± 4.3 years, height 181.6 ± 4.8 cm and body mass 78.7 ± 6.1 kg); creatine kinase (CK) was collected 2-days post-match for a 5-month period and at three different time points (Phase 1, Phase 2 and Phase 3); muscular strength (e.g. 4 repetition half-squat) was measured 3-day post-match. No significant change in CK and muscular force across three time points was found (F = 0.60, P = 0.56, η2 = 0.06 and F = 2.65, P = 0.10, η2 = 0.23, respectively). Muscular force was negatively correlated (moderate to very large) with CK. It can be concluded that players who produce greater lower body force as a result of being stronger in the lower limbs show reduced levels of CK 48 h post-match. Keywords: strength, muscle damage, recovery, soccer, creatine kinase
Introduction Professional soccer players are placed under continual domestic and often European and international competition demands (Carling & Dupont, 2011). Insufficient recovery between matches coupled with the prolonged increased physicality at the elite level puts players under a significant stress (Carling, Le Gall, & Dupont, 2012). Therefore, practitioners need a good understanding of the fatigue response to both training and match in addition to an awareness of how to effectively manage subsequent training loads. Achieving this will likely facilitate optimal preparation for subsequent performance in addition to reducing the risk of injury. Following match performance, a window of 72 h is considered sufficient to achieve restoration in pre-match values of physical performance benchmarks (Anderson et al., 2008; Carling et al., 2012; Mohr, Krustrup, & Bangsbo, 2003; Nedelec et al., 2012). This time period, however, may not be
afforded during a congested period of fixtures, commonplace in those teams also competing in European club competitions. The resultant effect is insufficient recovery and/or possible underperformance (Ra, Maeda, Higashino, Imai, & Miyakawa, 2014; Rollo, Impellizzeri, Zago, & Iaia, 2014). It would therefore seem important within a periodised training structure that estimates of match-related fatigue are determined, particularly between matches where alleviating post-match fatigue, regaining performance levels and minimise injury risk are deemed crucial (Nedelec et al., 2013; Ra et al., 2014). Repeatedly performing intense running actions have shown to impose high mechanical strain and induce muscle damage (Raastad et al., 2010; Silva et al., 2014; Young, Hepner, & Robbins, 2012). In terms of soccer, the seasonal effects of match-play have resulted in significant adjustments to biomarkers of physiological strain during the season whilst a return to normal has been documented during the
Correspondence: Adam Owen, Servette FC, Centre for Football Research, Geneva, Switzerland. E-mail: [email protected] © 2015 Taylor & Francis
The relationship between lower-limb strength and match-related muscle damage off-season (Silva et al., 2014). The requirement to continually perform high force eccentric actions such as changes in direction, accelerations and decelerations seem particularly damaging to the muscle (Raastad et al., 2010; Silva et al., 2014; Young et al., 2012). Creatine kinase (CK) is often used as a marker of the stress imposed on skeletal muscles during exercise (Brancaccio, Maffulli, & Limongelli, 2007; Mougios, 2007) and also for the monitoring of training load (Heisterberg et al., 2013). It (CK) has been used in several studies to measure the response to training and competition with values typically peaking 24–48 h after exercise cessation (Brancaccio et al., 2007; Meister, Der Funten, & Meyer, 2014; Young et al., 2012). The expression of serum CK is a highly individual response and thus baseline values are necessary to allow for an accurate interpretation (Lazarim et al., 2009). As previously recognised, the type of muscular action, intensity and duration of exercise imposed, in addition to training state (return to training from deconditioned state) influence the expression of serum CK (Magal et al., 2010). Strength and/or power qualities are commonly acknowledged as being important factors in many team sports (McGuigan, Wright, & Fleck, 2012). The rationale often being that it allows for athletes to be more explosive in actions and stronger in duals. Regardless, the focus has tended to be on developing strength capacities in preparation of forthcoming events. However, some studies have also alluded to strength playing a role in terms of recovery, or more appropriately influencing the response to fatigue (Johnston et al., 2013). It is well known that the demand of match-play in soccer induces a large proportion of eccentric work. Anecdotally, it has been offered that players who possess greater muscular strength and eccentric strength in particular may be more suited to dealing with the forces associated with these movements (Byrne, Twist, & Eston, 2004; Miyaguchi & Demura, 2008). Indeed, enhancing the stretch-shortening cycle capabilities of the muscle in combination with the repeated bout effect of undertaking regular strength training may attenuate the effects of muscle damage (Nosaka & Aoki, 2011). Therefore, greater muscular strength may reduce muscle damage following match-play and thus provide plausible justification to advocate regular undertaking of lower limb strength training throughout the soccer season. The purpose of this study is to examine the association between lower body strength capacities and the expression of post-match markers of muscle damage in elite level soccer players. Such information would allow coaches to better manage
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post-game recovery practices and reduce disruption to training. It is hypothesised that greater muscular strength is associated with reductions in post-game markers of muscle damage. Methods Participants Ten male professional soccer players participated in this investigation. Players participating within this study were at the time competing at the elite level of European soccer within the UEFA Champions League, and were recognised as the most successful domestic team in their league. At the initiation of the study, players involved had a mean ± SD age of 26.2 ± 3.9 (range: 18–36) years, stature of 181.9 ± 4.3 (170–192) cm and body mass of 77.9 ± 6.3 (62.5–93.6) kg. Percentage body fat was 10.1 ± 2.4 (5.1–16.3)%, and mean VO2max 52.8 ± 4.1 (52.1–68.6) ml · kg−1 · min−1. All participants had been playing soccer for 8 years or more and all but three of them were competing at international level. Participants were informed that they were free to withdraw from the study at any time. Procedures were in accordance with the Helsinki Declaration and approved by the local University ethical committee. Procedures To examine the association between lower limb strength levels of elite European soccer players, the expression of recovery markers post match-play, CK data and measurement of lower limb strength were collected over a 5-month competitive seasonal period (August–December) which included 26 matches (Figure 1). To correspond with the periodised training structure implemented, data collection was subsequently organised into three phases of 8-week blocks (Phase 1, 2, 3). CK data was always recorded 2-days post-match (between 10am and 10.30am) following a 1-day inactive period. As previous research has suggested, this particular sampling time point (i.e. 48 h post competitive match play) has been demonstrated to coincide with peak expression in serum CK (Coelho, Morandi, De Melo, & Silami-Garcia, 2011). Reflecting the number of matches played, 26 CK samples in total were collected per player, equating to 8 samples collected across Phase 1 and 9 during phases 2 and 3, respectively. For each player, CK samples were averaged across each phase to allow for comparative analysis across the investigation period. Assessment of lower limb strength capacities was performed at the end of each respective phase and always conducted 72 h following completion of the final match. This helped
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Figure 1. Testing timeline of CK and strength assessment across phases 1, 2 and 3.
to ensure a reduced fatigue effect in order to maintain consistency of testing and sample collection (Coelho et al., 2011). Creatine kinase assessment. Data from players who met the following inclusion criteria similar to Cohelo et al. (2011) participated in the study (n = 14). Inclusion criteria were that players had to have a minimum participation of 75 min per game, and played in a minimum of 12 games across the investigation phase. The mean number of games played per player was 15.6 ± 5.3. All blood sample collections were performed within the lab facilities of the club pre-training session. For the enzymatic measurement of plasma CK concentration, 32 µL capillary blood samples were obtained from the fingertip of the index finger of the selected players. The fingertip was cleaned with 95% ethanol and dried with cotton wool to remove excess liquid; an automatic lancet device was used to draw blood before a heparinised capillary tube (Reflotron Plus, Roche Diagnostics, Almere, The Netherlands) was used to collect the sample. The capillary blood sample was then immediately placed onto a CK test strip (Reflotron Plus, Roche Diagnostics) through the use of a pipette and analysed via the Boehringer Mannheim Reflotron Analyzer®. The individual CK samples taken 48 h post-match were then averaged and used for statistical assessment to show the relationship with force across the specified phases. Strength assessment (force). Force was tested by using the Keiser Air-300 Squat Machine (Keiser, Fresno, CA, USA) which is a pneumatic strength and power measurement machine. Players were familiarised with the testing equipment and regarded as being technically proficient as it had
been a part of their structured strength and conditioning programmes throughout the previous season (12 months) and pre-season phase pre-study. Prior to initiating the strength assessment, players were required to complete a 5-min bike warm up, followed by the performance of two submaximal warm up repetitions, at fixed resistances of 60 kg and 80 kg, respectively. After 2 min rest, participants performed four maximalvelocity repetitions, set at a fixed resistance of 120 kg. The fixed force (120 kg) testing protocol was similar to the method used by Andre et al. (2013). Players initiated the movement from an upright position, lowering into the half-squat position (i.e. 90-degree angle in the knee joint between femur and tibia) with the load distributed across their shoulders before initiating the upward phase which involved driving as fast as possible back to the upright position. The greatest output (force) generated within the four repetitions was used for the individuals comparison assessment. Statistical analysis The results are expressed as mean ± standard deviation (SD) and 95% confidence intervals (95% CIs). Normality assumption was verified using the Shapiro–Wilk W-test and visual inspection. A one-way analysis of variance (ANOVA) for repeated measures was used to examine the mean difference between the three strength testing phases in force and CK, respectively. Post-hoc analyses were performed using Least Significant Difference (LSD) test. The effect size was calculated for all ANOVAs with the use of a partial eta-squared (η2). Values of 0.01, 0.06 and above 0.15 were considered as small, medium and large, respectively (Cohen, 1988). Relationships between variables (Force and CK) were assessed using
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The relationship between lower-limb strength and match-related muscle damage Pearson’s product–moment correlation. According to Hopkins, Marshall, Batterham, and Hanin (2009), the magnitude of correlation coefficients was considered as trivial (r < 0.1), small (0.1 < r < 0.3), moderate (0.3 < r < 0.5), large (0.5 < r < 0.7), very large (0.7 < r < 0.9), nearly perfect (r > 0.9) and perfect (r = 1). Additionally, linear regressions were used to identify and determine the variance explained and coefficient of determination between force and CK. Statistical analyses were performed using SPSS software statistical package (SPSS Inc., Chicago, IL, version. 18.0). Statistical significance was set at P < 0.05.
Table II. Correlations among the muscular force and CK during the three periods. CK Phase 1 Force Phase 1 Phase 2 Phase 3
Phase 2
−0.46 (Moderate) −0.58 (Large) −0.44 (Moderate)
−0.41 (Moderate) −0.51 (Large) −0.33 (Moderate)
A
2100 Force (N)
Repeated-measure ANOVA results (Table I) revealed no significant change in CK across all testing time points (Phase 1, Phase 2 and Phase 3) (F = 0.60, P = 0.56, η2 = 0.06). Also, no significant main effect of muscular force was shown (F = 2.65, P = 0.10, η2 = 0.23). The relationship between muscular force and CK is provided in Table II. Muscular force was negatively correlated (moderate to very large) with CK during the three testing phases. The coefficients of determination (r2) are observed in the Figure 2.
−0.58 (Large) −0.73 (Very large) −0.66 (Large)
y = –0,38x + 2030,6 R2 = 0,21
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Results
Phase 3
1900 1700 1500 100
200
300
400
500
CK B
700
y = –0,37x + 2065 R2 = 0,26
2300
Discussion
600
(U.L–1)
The aim of the present study was to examine the relationship between lower-limb strength and match-related CK levels in professional European soccer players. Results from the investigation have revealed that there is a significant relationship between high force production capabilities of soccer players and the expression of reduced post-match markers of muscle damage as determined via the measurement of serum CK. Findings from the present study concur with other recent literature covering this research topic. Johnston, Gabbett, Jenkins,
Force (N)
2100 1900 1700 1500 100
200
300
400
500
600
700
800
CK (U.L–1) C y = –0,62x + 2133,6 R2 = 0,44
2300
CK (U/L)
Muscular force (W)
1700 1500 100
S.D.
Lower bound
Upper bound
Phase 1 (n = 8) 372 Phase 2 (n = 9) 382 Phase 3 (n = 9) 351 Phase 1 1888 Phase 2 1925 Phase 3 1916
177 166 158 148 120 147
245 263 238 1782 1839 1811
498 501 464 1994 2011 2022
Note: n = number of games within the phase.
1900
95% Confidence Interval
Mean
Phase
Force (N)
2100 Table I. Data in this table illustrate the muscular force and Creatine Kinase (CK).
200
300
400
500
600
700
CK (U.L–1) Figure 2. Linear regression between muscular force and CK in (A) Phase 1, (B) Phase 2 and (C) Phase 3.
and Hulin (2014) have confirmed that post-match fatigue was lower in players with well-developed physical qualities (i.e. high-intensity running ability
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and lower body strength) in elite level rugby league players. Further positive confirmation of the link between the lower body strength and power production of soccer players and its influence on fatigue or recovery markers proliferate justification for technical, physical and medical professionals to advocate regular lower limb strength training throughout the soccer season. As Raastad et al. (2010) explain, muscle damage is ascribed to mechanical disruption of the fibre, including membrane damage, myofibrillar disruptions characterised by myofillament disorganisation and loss of Z-disc integrity. The resulting structural changes may induce a temporal decline in muscle function as exhibited through a reduction in maximal force-generating capacity and imperatively impair physical performance. In this respect, monitoring the expression of muscle damage markers is important in understanding and managing post-match fatigue. It is inferred that CK and its relationship with muscle damage is a developing area for research in order to determine individual recovery strategies. A study by Young et al. (2012) revealed significant correlations between CK and running speeds >4 m · s−1 and accelerations and decelerations over a certain magnitude (moderate to high). Furthermore, it was suggested that may be a certain volume of movement at those speeds is required for that movement to be strongly associated with CK levels. In addition, when leaked into circulation in response to the manifestation of microtrauma (muscle damage) to structural and contractile components within the muscle fibre, CK serum activity has been proposed to mirror the high mechanical muscular stress experienced during intensive exercise performance (Meister et al., 2014). Within the literature there is body of evidence to suggest the existence of an indirect relationship between serum CK activity and the percentage of Type II muscle fibre (Magal et al., 2010). It has been suggested that these fibre types present a heightened susceptibility to damage and subsequently, more pronounced expressions in serum CK concentrations following eccentric mechanical stress (Jansson & Sylvén, 1985; Magal et al., 2010). Limitations Ensuring large participant participation within elite level soccer research is extremely difficult. The ability to meet participant inclusion criteria is often challenging due to numerous external influences such as suspensions, team selections, injury and illness. Throughout the investigation period, the inability to meet the inclusion criteria (i.e. a minimum participation of 75 min per game, and played
in a minimum of 12 games across the investigation phase) resulted in only 10 completed sets of data being obtained. Therefore, with respect to this investigation, future research should look to draw from baseline data for the variables measured, a larger participant pool in addition to increasing the sampling period in order to add greater strength to the association demonstrated between lower limb strength capacities and match-related muscle damage expression. In line with developing a clear relationship between lower limb strength capacities and muscle damage markers, future research would benefit from the implementation of an interventionbased study incorporating a control group. Conclusion The purpose of this investigation was to examine the association between lower body strength and the expression of markers of muscle damage as evaluated through CK responses following match play in professional soccer. Results of the present study support the suggested hypothesis in revealing an association between lower limb strength and CK assessment during the post-match recovery period. The potential for an improved recovery state post-match via integrated lower limb strength training may promote a positive performance effect and reduced injury risk. Further research is however required to confirm the duel response. Results from this particular investigation heightens the need for continued research within the elite level of the game for the incorporation of lower limb strength training throughout the season, with the focus of enhancing physical recovery and performance. Disclosure statement No potential conflict of interest was reported by the authors. References Anderson, H., Raastad, T., Nilsson, J., Paulsen, G., Garthe, I., & Kadi, F. (2008). Neuromuscular fatigue and recovery in elite female soccer: Effects of active recovery. Medicine & Science in Sports & Exercise, 40, 372–380. Andre, M. J., Fry, A., & Lane, M. T. (2013). Appropriate loads for peak-power during resisted sprinting on a non-motorized treadmill. Journal of Human Kinetics, 38, 161–167. Brancaccio, P., Maffulli, N., & Limongelli, F. M. (2007). Creatine kinase monitoring in sport medicine. British Medical Bulletin, 81–82, 209–230. Byrne, C., Twist, C., & Eston, R. (2004). Neuromuscular function after exercise-induced muscle damage: Theoretical and applied implications. Journal of Sports Medicine, 34, 49–69. Carling, C., & Dupont, G. (2011). Are declines in physical performance associated with a reduction in skill-related performance
The relationship between lower-limb strength and match-related muscle damage during professional soccer match-play? Journal of Sports Sciences, 29(1), 63–71. Carling, C., Le Gall, F., & Dupont, G. (2012). Are physical performance and injury risk in a professional soccer team in match-play affected over a prolonged period of fixture congestion? International Journal of Sports Physiology and Performance, 9 (3), 425–431. Coelho, D. B., Morandi, R. F., De Melo, M. A., & Silami-Garcia, E. (2011). Creatine kinase kinetics in professional soccer players during a competitive season Cinética da creatina quinase em jogadores de futebol profissional em uma temporada competitive. Rev Bras Cineantropom Desempenho Hum, 13(3), 189–194. Cohen, J. (1988). Statistical power analysis for the behavioural sciences (2nd ed.). Hove: Lawrence Erlbaum Associates. Heisterberg, M. F., Fahrenkrug, J., Krustrup, P., Storskov, A., Kjaer, M., & Andersen, J. L. (2013). Extensive monitoring through multiple blood samples in professional soccer players. Journal of Strength and Conditioning Research, 27(5), 1260–1271. Hopkins, W. G., Marshall, S. W., Batterham, A. M., & Hanin, J. (2009). Progressive statistics for studies in sports medicine and exercise science. Medicine & Science in Sports & Exercise, 41, 3–13. Jansson, E., & Sylvén, C. (1985). Creatine kinase MB and citrate synthase in type I and type II muscle fibres in trained and untrained men. European Journal of Applied Physiology and Occupational Physiology, 54, 207–209. Johnston, R. D., Gabbett, T. J., Jenkins, D. G., & Hulin, B. T. (2014). Influence of physical qualities on post match fatigue in rugby league players. Journal of Science and Medicine in Sport, 18(2), 209–213. Johnston, R. D., Gibson, N. V., Twist, C., Gabbett, T. J., MacNay, S. A., & MacFarlane, N. G. (2013). Physiological responses to an intensified period of rugby league competition. Journal of Strength and Conditioning Research, 27, 643–654. Lazarim, F. L., Antunes-Neto, J., Da Silva, F., Nunes, L., Bassini-Cameron, A., Cameron, L., . . . De Macedo, D. (2009). The upper values of plasma creatine kinase of professional soccer players during the Brazilian National Championship. Journal of Science and Medicine in Sport, 12 (1), 85–90. Magal, M., Dumke, C. L., Zea, G., Urbiztondo, C., Cavill, M. J., Triplett, N. T., . . . Epstein, Y. (2010). Relationship between serum creatine kinase activity following exercise-induced muscle damage and muscle fibre composition. Journal of Sports Sciences, 28(3), 257–266. McGuigan, M. R., Wright, G. A., & Fleck, S. J. (2012). Strength training for athletes: Does it really help sports
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performance? International Journal of Sports Physiology and Performance, 7(1), 2–5. Meister, S., Der Funten, K., & Meyer, T. (2014). Repeated monitoring of blood parameters for evaluating strain and overload in elite professional players: Is it justified? Journal of Sports Sciences, 32(13), 1328–1331. Miyaguchi, K., & Demura, S. (2008). Relationships between stretch-shortening cycle performance and maximum muscle strength. Journal of Strength and Conditioning Research, 22, 19–24. Mohr, M., Krustrup, P., & Bangsbo, J. (2003). Match performance of high-standard soccer players with special reference to development of fatigue. Journal of Medicine and Sports Science, 21(7), 519–528. Mougios, V. (2007). Reference intervals for serum creatine kinase in athletes. British Journal of Sports Medicine, 41, 674–678. Nedelec, M., McCall, A., Carling, C., Legall, F., Berthoin, B., & Dupont, G. (2012). Recovery in soccer: Part I - post-match fatigue and time course of recovery. Journal of Sports Medicine and Science, 42(12), 997–1015. Nedelec, M., McCall, A., Carling, C., Legall, F., Berthoin, B., & Dupont, G. (2013). Recovery in soccer: Part II – Recovery strategies. Journal of Sports Med, 43, 9–22. Nosaka, K. J., & Aoki, M. S. (2011). Repeated bout effect: Research update and future perspective. Brazilian Journal of Biomotricity, 5(1), 5–15. Ra, S.-G., Maeda, S., Higashino, R., Imai, T., & Miyakawa, S. (2014). Metabolomics of salivary fatigue markers in soccer players after consecutive games. Journal of Applied Physiology, Nutrition and Metabolism, 39(10), 1120–1126. Raastad, T., Owe, S. G., Paulsen, G., Enns, D., Overguard, K., Crameri, R., . . . Hallen, J. (2010). Changes in calpain activity, muscle structure, and function after eccentric exercise. Journal of Medicine and Science in Sport and Exercise, 42(1), 86–95. Rollo, I., Impellizzeri, F. M., Zago, M., & Iaia, F. M. (2014). Effects of 1 versus 2 games a week on physical and subjective scores of subelite soccer players. International Journal of Sports Physiology and Performance, 9(3), 425–431. Silva, J. R., Rebelo, A., Marques, F., Pereira, L., Seabra, A., & Magalhães, A. (2014). Biochemical impact of soccer: An analysis of hormonal, muscle damage, and redox markers during the season. Journal of Applied Physiology, Nutrition and Metabolism, 39(4), 432–438. Young, W. B., Hepner, J., & Robbins, D. W. (2012). Movement demands in Australian rules football as indicators of muscle damage. Journal of Strength and Conditioning Research, 26(2), 492–496.
ISSN: 0264-0414 (Print) 1466-447X (Online) Journal homepage: http://www.tandfonline.com/loi/rjsp20
The relationship between lower-limb strength and match-related muscle damage in elite level professional European soccer players Adam Owen, Gordon Dunlop, Mehdi Rouissi, Moktar Chtara, Darren Paul, Hassane Zouhal & Del P. Wong To cite this article: Adam Owen, Gordon Dunlop, Mehdi Rouissi, Moktar Chtara, Darren Paul, Hassane Zouhal & Del P. Wong (2015) The relationship between lower-limb strength and match-related muscle damage in elite level professional European soccer players, Journal of Sports Sciences, 33:20, 2100-2105, DOI: 10.1080/02640414.2015.1064155 To link to this article: http://dx.doi.org/10.1080/02640414.2015.1064155
Published online: 09 Jul 2015.
Submit your article to this journal
Article views: 849
View related articles
View Crossmark data
Citing articles: 1 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=rjsp20 Download by: [FU Berlin]
Date: 27 November 2016, At: 11:49
Journal of Sports Sciences, 2015 Vol. 33, No. 20, 2100–2105, http://dx.doi.org/10.1080/02640414.2015.1064155
The relationship between lower-limb strength and match-related muscle damage in elite level professional European soccer players
ADAM OWEN1,2, GORDON DUNLOP1, MEHDI ROUISSI3, MOKTAR CHTARA4, DARREN PAUL5, HASSANE ZOUHAL6 & DEL P. WONG7 1
Servette FC, Centre for Football Research, Geneva, Switzerland, 2Centre de Recherch et d’Innovation sur le Sport, Universite Claude Bernard Lyon.1, Lyon, France, 3CNMSS, El Menzah, Tunisia, 4CNMSS, Tunis, Tunisia, 5ASPETAR, Research dept, ASPETAR research in sport, Doha, Qatar, 6Universitie Rennes2, Sport Science, Avenue Charles Tillon, Rennes, France and 7Human Performance Laboratory, Technological and Higher Education Institute of Hong Kong, Hong Kong, China (Accepted 7 June 2015)
Abstract In professional soccer, the benefits of lower limb strength training have been advocated. However, from an aspect of performance development, specifically with respect to expression of fatigue and injury prevention, the advantages of increased lower body strength have received limited attention at the elite level of the game. The primary aim of this cross-sectional investigation was to examine the association between lower body strength and the expression of markers of fatigue as evaluated through muscle damage assessment following match play in professional soccer players. Ten male professional soccer players participated in this investigation (mean ± SD age 26.2 ± 4.3 years, height 181.6 ± 4.8 cm and body mass 78.7 ± 6.1 kg); creatine kinase (CK) was collected 2-days post-match for a 5-month period and at three different time points (Phase 1, Phase 2 and Phase 3); muscular strength (e.g. 4 repetition half-squat) was measured 3-day post-match. No significant change in CK and muscular force across three time points was found (F = 0.60, P = 0.56, η2 = 0.06 and F = 2.65, P = 0.10, η2 = 0.23, respectively). Muscular force was negatively correlated (moderate to very large) with CK. It can be concluded that players who produce greater lower body force as a result of being stronger in the lower limbs show reduced levels of CK 48 h post-match. Keywords: strength, muscle damage, recovery, soccer, creatine kinase
Introduction Professional soccer players are placed under continual domestic and often European and international competition demands (Carling & Dupont, 2011). Insufficient recovery between matches coupled with the prolonged increased physicality at the elite level puts players under a significant stress (Carling, Le Gall, & Dupont, 2012). Therefore, practitioners need a good understanding of the fatigue response to both training and match in addition to an awareness of how to effectively manage subsequent training loads. Achieving this will likely facilitate optimal preparation for subsequent performance in addition to reducing the risk of injury. Following match performance, a window of 72 h is considered sufficient to achieve restoration in pre-match values of physical performance benchmarks (Anderson et al., 2008; Carling et al., 2012; Mohr, Krustrup, & Bangsbo, 2003; Nedelec et al., 2012). This time period, however, may not be
afforded during a congested period of fixtures, commonplace in those teams also competing in European club competitions. The resultant effect is insufficient recovery and/or possible underperformance (Ra, Maeda, Higashino, Imai, & Miyakawa, 2014; Rollo, Impellizzeri, Zago, & Iaia, 2014). It would therefore seem important within a periodised training structure that estimates of match-related fatigue are determined, particularly between matches where alleviating post-match fatigue, regaining performance levels and minimise injury risk are deemed crucial (Nedelec et al., 2013; Ra et al., 2014). Repeatedly performing intense running actions have shown to impose high mechanical strain and induce muscle damage (Raastad et al., 2010; Silva et al., 2014; Young, Hepner, & Robbins, 2012). In terms of soccer, the seasonal effects of match-play have resulted in significant adjustments to biomarkers of physiological strain during the season whilst a return to normal has been documented during the
Correspondence: Adam Owen, Servette FC, Centre for Football Research, Geneva, Switzerland. E-mail: [email protected] © 2015 Taylor & Francis
The relationship between lower-limb strength and match-related muscle damage off-season (Silva et al., 2014). The requirement to continually perform high force eccentric actions such as changes in direction, accelerations and decelerations seem particularly damaging to the muscle (Raastad et al., 2010; Silva et al., 2014; Young et al., 2012). Creatine kinase (CK) is often used as a marker of the stress imposed on skeletal muscles during exercise (Brancaccio, Maffulli, & Limongelli, 2007; Mougios, 2007) and also for the monitoring of training load (Heisterberg et al., 2013). It (CK) has been used in several studies to measure the response to training and competition with values typically peaking 24–48 h after exercise cessation (Brancaccio et al., 2007; Meister, Der Funten, & Meyer, 2014; Young et al., 2012). The expression of serum CK is a highly individual response and thus baseline values are necessary to allow for an accurate interpretation (Lazarim et al., 2009). As previously recognised, the type of muscular action, intensity and duration of exercise imposed, in addition to training state (return to training from deconditioned state) influence the expression of serum CK (Magal et al., 2010). Strength and/or power qualities are commonly acknowledged as being important factors in many team sports (McGuigan, Wright, & Fleck, 2012). The rationale often being that it allows for athletes to be more explosive in actions and stronger in duals. Regardless, the focus has tended to be on developing strength capacities in preparation of forthcoming events. However, some studies have also alluded to strength playing a role in terms of recovery, or more appropriately influencing the response to fatigue (Johnston et al., 2013). It is well known that the demand of match-play in soccer induces a large proportion of eccentric work. Anecdotally, it has been offered that players who possess greater muscular strength and eccentric strength in particular may be more suited to dealing with the forces associated with these movements (Byrne, Twist, & Eston, 2004; Miyaguchi & Demura, 2008). Indeed, enhancing the stretch-shortening cycle capabilities of the muscle in combination with the repeated bout effect of undertaking regular strength training may attenuate the effects of muscle damage (Nosaka & Aoki, 2011). Therefore, greater muscular strength may reduce muscle damage following match-play and thus provide plausible justification to advocate regular undertaking of lower limb strength training throughout the soccer season. The purpose of this study is to examine the association between lower body strength capacities and the expression of post-match markers of muscle damage in elite level soccer players. Such information would allow coaches to better manage
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post-game recovery practices and reduce disruption to training. It is hypothesised that greater muscular strength is associated with reductions in post-game markers of muscle damage. Methods Participants Ten male professional soccer players participated in this investigation. Players participating within this study were at the time competing at the elite level of European soccer within the UEFA Champions League, and were recognised as the most successful domestic team in their league. At the initiation of the study, players involved had a mean ± SD age of 26.2 ± 3.9 (range: 18–36) years, stature of 181.9 ± 4.3 (170–192) cm and body mass of 77.9 ± 6.3 (62.5–93.6) kg. Percentage body fat was 10.1 ± 2.4 (5.1–16.3)%, and mean VO2max 52.8 ± 4.1 (52.1–68.6) ml · kg−1 · min−1. All participants had been playing soccer for 8 years or more and all but three of them were competing at international level. Participants were informed that they were free to withdraw from the study at any time. Procedures were in accordance with the Helsinki Declaration and approved by the local University ethical committee. Procedures To examine the association between lower limb strength levels of elite European soccer players, the expression of recovery markers post match-play, CK data and measurement of lower limb strength were collected over a 5-month competitive seasonal period (August–December) which included 26 matches (Figure 1). To correspond with the periodised training structure implemented, data collection was subsequently organised into three phases of 8-week blocks (Phase 1, 2, 3). CK data was always recorded 2-days post-match (between 10am and 10.30am) following a 1-day inactive period. As previous research has suggested, this particular sampling time point (i.e. 48 h post competitive match play) has been demonstrated to coincide with peak expression in serum CK (Coelho, Morandi, De Melo, & Silami-Garcia, 2011). Reflecting the number of matches played, 26 CK samples in total were collected per player, equating to 8 samples collected across Phase 1 and 9 during phases 2 and 3, respectively. For each player, CK samples were averaged across each phase to allow for comparative analysis across the investigation period. Assessment of lower limb strength capacities was performed at the end of each respective phase and always conducted 72 h following completion of the final match. This helped
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Figure 1. Testing timeline of CK and strength assessment across phases 1, 2 and 3.
to ensure a reduced fatigue effect in order to maintain consistency of testing and sample collection (Coelho et al., 2011). Creatine kinase assessment. Data from players who met the following inclusion criteria similar to Cohelo et al. (2011) participated in the study (n = 14). Inclusion criteria were that players had to have a minimum participation of 75 min per game, and played in a minimum of 12 games across the investigation phase. The mean number of games played per player was 15.6 ± 5.3. All blood sample collections were performed within the lab facilities of the club pre-training session. For the enzymatic measurement of plasma CK concentration, 32 µL capillary blood samples were obtained from the fingertip of the index finger of the selected players. The fingertip was cleaned with 95% ethanol and dried with cotton wool to remove excess liquid; an automatic lancet device was used to draw blood before a heparinised capillary tube (Reflotron Plus, Roche Diagnostics, Almere, The Netherlands) was used to collect the sample. The capillary blood sample was then immediately placed onto a CK test strip (Reflotron Plus, Roche Diagnostics) through the use of a pipette and analysed via the Boehringer Mannheim Reflotron Analyzer®. The individual CK samples taken 48 h post-match were then averaged and used for statistical assessment to show the relationship with force across the specified phases. Strength assessment (force). Force was tested by using the Keiser Air-300 Squat Machine (Keiser, Fresno, CA, USA) which is a pneumatic strength and power measurement machine. Players were familiarised with the testing equipment and regarded as being technically proficient as it had
been a part of their structured strength and conditioning programmes throughout the previous season (12 months) and pre-season phase pre-study. Prior to initiating the strength assessment, players were required to complete a 5-min bike warm up, followed by the performance of two submaximal warm up repetitions, at fixed resistances of 60 kg and 80 kg, respectively. After 2 min rest, participants performed four maximalvelocity repetitions, set at a fixed resistance of 120 kg. The fixed force (120 kg) testing protocol was similar to the method used by Andre et al. (2013). Players initiated the movement from an upright position, lowering into the half-squat position (i.e. 90-degree angle in the knee joint between femur and tibia) with the load distributed across their shoulders before initiating the upward phase which involved driving as fast as possible back to the upright position. The greatest output (force) generated within the four repetitions was used for the individuals comparison assessment. Statistical analysis The results are expressed as mean ± standard deviation (SD) and 95% confidence intervals (95% CIs). Normality assumption was verified using the Shapiro–Wilk W-test and visual inspection. A one-way analysis of variance (ANOVA) for repeated measures was used to examine the mean difference between the three strength testing phases in force and CK, respectively. Post-hoc analyses were performed using Least Significant Difference (LSD) test. The effect size was calculated for all ANOVAs with the use of a partial eta-squared (η2). Values of 0.01, 0.06 and above 0.15 were considered as small, medium and large, respectively (Cohen, 1988). Relationships between variables (Force and CK) were assessed using
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The relationship between lower-limb strength and match-related muscle damage Pearson’s product–moment correlation. According to Hopkins, Marshall, Batterham, and Hanin (2009), the magnitude of correlation coefficients was considered as trivial (r < 0.1), small (0.1 < r < 0.3), moderate (0.3 < r < 0.5), large (0.5 < r < 0.7), very large (0.7 < r < 0.9), nearly perfect (r > 0.9) and perfect (r = 1). Additionally, linear regressions were used to identify and determine the variance explained and coefficient of determination between force and CK. Statistical analyses were performed using SPSS software statistical package (SPSS Inc., Chicago, IL, version. 18.0). Statistical significance was set at P < 0.05.
Table II. Correlations among the muscular force and CK during the three periods. CK Phase 1 Force Phase 1 Phase 2 Phase 3
Phase 2
−0.46 (Moderate) −0.58 (Large) −0.44 (Moderate)
−0.41 (Moderate) −0.51 (Large) −0.33 (Moderate)
A
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Repeated-measure ANOVA results (Table I) revealed no significant change in CK across all testing time points (Phase 1, Phase 2 and Phase 3) (F = 0.60, P = 0.56, η2 = 0.06). Also, no significant main effect of muscular force was shown (F = 2.65, P = 0.10, η2 = 0.23). The relationship between muscular force and CK is provided in Table II. Muscular force was negatively correlated (moderate to very large) with CK during the three testing phases. The coefficients of determination (r2) are observed in the Figure 2.
−0.58 (Large) −0.73 (Very large) −0.66 (Large)
y = –0,38x + 2030,6 R2 = 0,21
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Results
Phase 3
1900 1700 1500 100
200
300
400
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CK B
700
y = –0,37x + 2065 R2 = 0,26
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Discussion
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(U.L–1)
The aim of the present study was to examine the relationship between lower-limb strength and match-related CK levels in professional European soccer players. Results from the investigation have revealed that there is a significant relationship between high force production capabilities of soccer players and the expression of reduced post-match markers of muscle damage as determined via the measurement of serum CK. Findings from the present study concur with other recent literature covering this research topic. Johnston, Gabbett, Jenkins,
Force (N)
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300
400
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CK (U.L–1) C y = –0,62x + 2133,6 R2 = 0,44
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CK (U/L)
Muscular force (W)
1700 1500 100
S.D.
Lower bound
Upper bound
Phase 1 (n = 8) 372 Phase 2 (n = 9) 382 Phase 3 (n = 9) 351 Phase 1 1888 Phase 2 1925 Phase 3 1916
177 166 158 148 120 147
245 263 238 1782 1839 1811
498 501 464 1994 2011 2022
Note: n = number of games within the phase.
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95% Confidence Interval
Mean
Phase
Force (N)
2100 Table I. Data in this table illustrate the muscular force and Creatine Kinase (CK).
200
300
400
500
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CK (U.L–1) Figure 2. Linear regression between muscular force and CK in (A) Phase 1, (B) Phase 2 and (C) Phase 3.
and Hulin (2014) have confirmed that post-match fatigue was lower in players with well-developed physical qualities (i.e. high-intensity running ability
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and lower body strength) in elite level rugby league players. Further positive confirmation of the link between the lower body strength and power production of soccer players and its influence on fatigue or recovery markers proliferate justification for technical, physical and medical professionals to advocate regular lower limb strength training throughout the soccer season. As Raastad et al. (2010) explain, muscle damage is ascribed to mechanical disruption of the fibre, including membrane damage, myofibrillar disruptions characterised by myofillament disorganisation and loss of Z-disc integrity. The resulting structural changes may induce a temporal decline in muscle function as exhibited through a reduction in maximal force-generating capacity and imperatively impair physical performance. In this respect, monitoring the expression of muscle damage markers is important in understanding and managing post-match fatigue. It is inferred that CK and its relationship with muscle damage is a developing area for research in order to determine individual recovery strategies. A study by Young et al. (2012) revealed significant correlations between CK and running speeds >4 m · s−1 and accelerations and decelerations over a certain magnitude (moderate to high). Furthermore, it was suggested that may be a certain volume of movement at those speeds is required for that movement to be strongly associated with CK levels. In addition, when leaked into circulation in response to the manifestation of microtrauma (muscle damage) to structural and contractile components within the muscle fibre, CK serum activity has been proposed to mirror the high mechanical muscular stress experienced during intensive exercise performance (Meister et al., 2014). Within the literature there is body of evidence to suggest the existence of an indirect relationship between serum CK activity and the percentage of Type II muscle fibre (Magal et al., 2010). It has been suggested that these fibre types present a heightened susceptibility to damage and subsequently, more pronounced expressions in serum CK concentrations following eccentric mechanical stress (Jansson & Sylvén, 1985; Magal et al., 2010). Limitations Ensuring large participant participation within elite level soccer research is extremely difficult. The ability to meet participant inclusion criteria is often challenging due to numerous external influences such as suspensions, team selections, injury and illness. Throughout the investigation period, the inability to meet the inclusion criteria (i.e. a minimum participation of 75 min per game, and played
in a minimum of 12 games across the investigation phase) resulted in only 10 completed sets of data being obtained. Therefore, with respect to this investigation, future research should look to draw from baseline data for the variables measured, a larger participant pool in addition to increasing the sampling period in order to add greater strength to the association demonstrated between lower limb strength capacities and match-related muscle damage expression. In line with developing a clear relationship between lower limb strength capacities and muscle damage markers, future research would benefit from the implementation of an interventionbased study incorporating a control group. Conclusion The purpose of this investigation was to examine the association between lower body strength and the expression of markers of muscle damage as evaluated through CK responses following match play in professional soccer. Results of the present study support the suggested hypothesis in revealing an association between lower limb strength and CK assessment during the post-match recovery period. The potential for an improved recovery state post-match via integrated lower limb strength training may promote a positive performance effect and reduced injury risk. Further research is however required to confirm the duel response. Results from this particular investigation heightens the need for continued research within the elite level of the game for the incorporation of lower limb strength training throughout the season, with the focus of enhancing physical recovery and performance. Disclosure statement No potential conflict of interest was reported by the authors. References Anderson, H., Raastad, T., Nilsson, J., Paulsen, G., Garthe, I., & Kadi, F. (2008). Neuromuscular fatigue and recovery in elite female soccer: Effects of active recovery. Medicine & Science in Sports & Exercise, 40, 372–380. Andre, M. J., Fry, A., & Lane, M. T. (2013). Appropriate loads for peak-power during resisted sprinting on a non-motorized treadmill. Journal of Human Kinetics, 38, 161–167. Brancaccio, P., Maffulli, N., & Limongelli, F. M. (2007). Creatine kinase monitoring in sport medicine. British Medical Bulletin, 81–82, 209–230. Byrne, C., Twist, C., & Eston, R. (2004). Neuromuscular function after exercise-induced muscle damage: Theoretical and applied implications. Journal of Sports Medicine, 34, 49–69. Carling, C., & Dupont, G. (2011). Are declines in physical performance associated with a reduction in skill-related performance
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performance? International Journal of Sports Physiology and Performance, 7(1), 2–5. Meister, S., Der Funten, K., & Meyer, T. (2014). Repeated monitoring of blood parameters for evaluating strain and overload in elite professional players: Is it justified? Journal of Sports Sciences, 32(13), 1328–1331. Miyaguchi, K., & Demura, S. (2008). Relationships between stretch-shortening cycle performance and maximum muscle strength. Journal of Strength and Conditioning Research, 22, 19–24. Mohr, M., Krustrup, P., & Bangsbo, J. (2003). Match performance of high-standard soccer players with special reference to development of fatigue. Journal of Medicine and Sports Science, 21(7), 519–528. Mougios, V. (2007). Reference intervals for serum creatine kinase in athletes. British Journal of Sports Medicine, 41, 674–678. Nedelec, M., McCall, A., Carling, C., Legall, F., Berthoin, B., & Dupont, G. (2012). Recovery in soccer: Part I - post-match fatigue and time course of recovery. Journal of Sports Medicine and Science, 42(12), 997–1015. Nedelec, M., McCall, A., Carling, C., Legall, F., Berthoin, B., & Dupont, G. (2013). Recovery in soccer: Part II – Recovery strategies. Journal of Sports Med, 43, 9–22. Nosaka, K. J., & Aoki, M. S. (2011). Repeated bout effect: Research update and future perspective. Brazilian Journal of Biomotricity, 5(1), 5–15. Ra, S.-G., Maeda, S., Higashino, R., Imai, T., & Miyakawa, S. (2014). Metabolomics of salivary fatigue markers in soccer players after consecutive games. Journal of Applied Physiology, Nutrition and Metabolism, 39(10), 1120–1126. Raastad, T., Owe, S. G., Paulsen, G., Enns, D., Overguard, K., Crameri, R., . . . Hallen, J. (2010). Changes in calpain activity, muscle structure, and function after eccentric exercise. Journal of Medicine and Science in Sport and Exercise, 42(1), 86–95. Rollo, I., Impellizzeri, F. M., Zago, M., & Iaia, F. M. (2014). Effects of 1 versus 2 games a week on physical and subjective scores of subelite soccer players. International Journal of Sports Physiology and Performance, 9(3), 425–431. Silva, J. R., Rebelo, A., Marques, F., Pereira, L., Seabra, A., & Magalhães, A. (2014). Biochemical impact of soccer: An analysis of hormonal, muscle damage, and redox markers during the season. Journal of Applied Physiology, Nutrition and Metabolism, 39(4), 432–438. Young, W. B., Hepner, J., & Robbins, D. W. (2012). Movement demands in Australian rules football as indicators of muscle damage. Journal of Strength and Conditioning Research, 26(2), 492–496.
