Sports Med DOI 10.1007/s40279-014-0191-9
LETTER TO THE EDITOR
Dr. Boullosa’s Forgotten Pieces Don’t Fit the Puzzle Martin Buchheit • Paul B. Laursen
Springer International Publishing Switzerland 2014
We appreciate the opportunity to respond to Dr. Boullosa’s letter of concern [1] on issues brought forth in our two-part review on high-intensity interval training (HIT) [2, 3]. However, we were surprised to read the letter’s content, feeling generally that most comments were off topic, and accordingly offer little to assist the practitioner. Nevertheless, we will use this opportunity to elaborate on certain principles and in doing so outline why his so-called ‘‘forgotten pieces’’ do not fit the training programme puzzle. His first critique of our review [2] was that there was no comment as to how progressive exercise test protocol design influences the relationship between the velocity/ _ 2max) and perpower at maximal oxygen uptake (v/pVO formance. This is simply incorrect. Section 2.5 of our review extends to more than a full page of printed text describing in detail the history, theory, as well as measurement techniques practitioners can perform in both the laboratory and the field to determine appropriate values, as _ 2max well as their limitations. We state clearly how ‘‘vVO [determination] is method [4] and protocol-dependent [5]’’. It would therefore be implied that the magnitude of the _ 2max and performance would relationship between vVO comparatively be affected. We did not elaborate further on this point, as such discourse would be superfluous within the context of the review, which focused on HIT prescription, and not performance prediction. For these reasons, Dr. Boullosa’s first piece doesn’t fit.
M. Buchheit (&) Sport Science Department, Myorobie Association, 73700 Montvalezan, France e-mail: [email protected] P. B. Laursen High Performance Sport New Zealand, Auckland, New Zealand
His second critique was that ‘‘there was no reference […] to how [anaerobic speed reserve] ASR could be influenced by the method [used] for [maximal sprinting speed] MSS determination’’. While the point is valid, there are a limited number of known methods for determining MSS, and these unlikely produce differences in MSS as _ 2max or the final speed reached great as those seen with vVO during an incremental test (VIncTest) [2]. In practice, the use of a flying 10- [6] or 20-m [7, 8] time is probably the most common method of determination, although peak instantaneous speed can also be measured now with radar gun technology [9]. The difference between these methods is generally less than *2 % (personal observations), which is substantially lower than the possible *20 % difference _ 2max/VIncTest determination that can be observed for vVO [2]. Moreover, the typical error of measurement for MSS (1 %) is also clearly lower than that of VIncTest (3.5 %) [10]. Taken together, these data show that the determination of ASR is less likely to be affected by variations in _ 2max/VIncTest estimation, and explain why we MSS than vVO chose against elaborating further on this point in our review [2]. Dr. Boullosa goes on to claim that ‘‘the practicality of the 30-15 Intermittent Fitness Test (30-15IFT) for evaluating simultaneously different locomotor abilities and ASR is contradictory stricto sensu with the previous definition of ASR’’, and offers instead ‘‘a potentially simple and timesaving alternative evaluation of ASR with the recording of a maximum sprint test performed 3–5 min after an incre_ 2max determination [7]’’. The first part mental test for vVO of the comment is unclear to us, since it is now known that _ 2max/VIncTest and MSS [11]. VIFT is sensitive to both vVO The ‘‘dual sensitivity’’ of the 30-15IFT motivated our comments around the ‘‘simultaneous’’ evaluation of
123
M. Buchheit, P. B. Laursen
a
Velocity
MSS (29 km/h)
anaerobic speed reserve
VIFT (21 km/h)
vVO2max (18 km/h)
Time
b
Velocity
MSS (32 km/h)
anaerobic speed reserve
VIFT (22 km/h) vVO2max (18 km/h)
Time Fig. 1 Illustration of the importance of the anaerobic speed reserve (ASR) contribution towards reaching the final speed during the 30-15 Intermittent Fitness Test (VIFT). a Once the minimum speed required _ 2max) is reached, the additional to elicit maximal oxygen uptake (vVO energy provided during the remaining stages is derived mostly from _ 2max, the greater anaerobic sources. Therefore, for a given vVO maximal sprinting speed (MSS) and, hence, ASR (or at least the greater the proportion used), the greater the number of ‘supra_ 2max’ stages that will be completed (and the faster the VIFT). b vVO
This player having a greater ASR is able to reach, for a similar _ 2max, two further stages during the 30-15IFT (1 km/h). Since the vVO ASR (or the proportion used) also influences what can be achieved during high-intensity intermittent runs, the use of the VIFT, and not _ 2max, enables the programming of similar (anaerobic and vVO neuromuscular) training loads in workouts for each player. Adapted from Buchheit [37], with permission
different locomotor abilities. We showed that, while the first _ 2max/VIncTest, MSS is likely to be determinant of VIFT is vVO the secondary influencing variable [11]. If we take, for example, two young football players presenting with similar _ 2max/VIncTest scores, the athlete with the faster MSS also vVO has the faster VIFT (Fig. 1, adapted from Buchheit [37], with permission). The other part of Dr. Boullosa’s comment suggesting assessment of MSS following the incremental test is also at odds with the current practices that we are personally aware of, both for team sports and distance running. While standing [12] and flying [7, 8] 20-m sprint tests have been used in the literature with endurance athletes after exhaustive exercise, such procedures are problematic for assessing MSS (i.e. 10-m splits likely allow a better assessment than 20-m ones, and the fastest split is not necessarily derived from the last one [6]). Since athletes must
sprint maximally over at least 40–50 m to ensure their MSS is captured, coaches (irrespective of the sport) tend to be (in our experience) reluctant to assess MSS post-incremental test, mainly due to the increased hamstring and adductor injury risk [13]. The assessment of MSS following an incremental test is also questionable from a performance standpoint, since MSS could potentially be impaired, especially in team-sport athletes. While some endurance athletes might maintain sprinting speed [14], the magnitude of the performance decrement post-exhaustive effort is largely and inversely correlated with initial sprinting speed [8]; faster team sport players therefore would likely incur a large impairment to MSS using such an approach. Since this potentially serious effect is athlete background- and locomotor profile-dependent, it makes more sense practically to assess MSS on a separate occasion, when all athletes have
123
Letter to the Editor
_ 2max/VIncTest [11, 15]. In light of recovered from the vVO these arguments, we believe Dr. Boullosa’s second piece does not fit the puzzle. In Dr. Boullosa’s third critique, he states that ‘‘there is no actual evidence supporting the usefulness of ASR for individualizing training intensity prescription’’. While we agree that a comprehensive study comparing the acute and long-term physiological and performance responses of HIT _ 2max/VIncTest versus %ASR has yet to sessions based on vVO be published, we can provide evidence to support the use of this method to individualise HIT (Fig. 2). First, the approach is used across a considerable number of (team) sports worldwide, and has been now for more than 10 years, which is proof of its practicality, interest and
120
40
100
ASR (%)
a
35
80
Player A Player B Player C
60 40
Speed (km/h)
20 0
30 0
50
100 150 200 250 300
Time (s)
25 20 15 10 0
50
100
MAS ASR
150
200
250
Time (s)
%VIFT
Work interval duration
d
20
20
20
15
15
15 10
10
5
5
0
0
A
B
C
n
25
%
km/h
b Work interval speed c
#of work intervals
10 5 0
A
B
C
A
B
C
Fig. 2 a Predicted [38] speed/duration relationship in three soccer players with different maximal sprinting (MSS) and aerobic (MAS) speeds and peak speed reached in the 30-15 Intermittent Fitness Test (VIFT). Player A: 32, 18 and 21 km/h for MSS, MAS and VIFT, respectively; Player B: 36, 16 and 20.5 km/h; and Player C: 35, 14 and 18.5 km/h. Despite different absolute speeds at a given duration, when expressed in relation to the anaerobic speed reserve (inserted graph), these differences are eliminated. b Work interval speed in players A, B and C during high-intensity interval training (HIT) with short intervals (i.e. 15 s) prescribed at 125 % of MAS, 25 % of the anaerobic speed reserve (ASR) or 100 % of VIFT. c Work interval duration expressed as a percentage of the predicted [38] time to exhaustion at that speed. d Number of intervals required to match the predicted surpramaximal distance capacity (i.e. the distance covered under the individual curve shown in a). c and d show that using ASR or VIFT instead of MAS as the reference running speed to prescribe work interval intensity allows a better standardisation of training load during HIT in athletes with different locomotor profiles
usefulness (i.e. ‘best practice’ theory). Second, the ASR approach is taught in well-established and respected strength and conditioning courses throughout the world (e.g. France, Spain, Italy, Germany, Switzerland, USA, Australia, New Zealand), and has been the subject matter of publications by other groups (e.g. Heaney and Willey [16]). Last, as with the smaller between-athlete variations _ 2max/VIncTestin acute cardiac responses to VIFT versus vVO based HIT sessions [17], we have observed a smaller between-athlete variation in time-to-exhaustion using per_ 2max/VIncTest centage of ASR than using percentage of vVO (31 vs. 55 % during a 15 s at 95 % VIFT/15 s passive HIT, unpublished data). This clearly shows that using the entire locomotor profile (or at least VIFT) to prescribe running_ 2max, based HIT with short intervals, rather than only vVO allows the standardisation of relative exercise intensity at the individual level. The direct consequence of this intensity standardisation is that the work interval duration represents a constant fraction of the predicted time to exhaustion at this relative intensity for all athletes. Along these lines, the number of work intervals required to match the predicted supramaximal distance capacity also remains constant for all athletes (Fig. 2). Dr. Boullosa goes on to emphasise that ‘‘the improve_ 2max are independent objectives ment of both MSS and vVO that depend on the requirements of a specific sport.’’ We of course concur, as we highlighted in Fig. 1 from the first part of our review [2], where we outline how training objectives should relate to the athlete’s profile, sport and training cycle. But we did not suggest that variation in HIT formats can be used specifically to improve either MSS or _ 2max in isolation. It is clear that if the training objective vVO is to improve MSS, isolated speed/strength sessions would be recommended, and not HIT sessions [18, 19], as shown also in Fig. 1 of the first part of the review [2]. In addition, the remaining part of Dr. Boullosa’s comment, where reference is made to acceleration capacity in team sports, shows that he fails to consider separately the physiological and neuromuscular requirements of (1) a given training session aimed at improving an athlete’s physiology, and (2) competitive situations. While the principle of training specificity should not be forgotten, excessive reliance on competition-like training content (e.g. match replication) has its limitations [20, 21]. The main interest in determining ASR is to account for the athletes’ entire locomotor profile when performing a run-based HIT session at high but not maximal speed, which has implications for acute physiological and performance responses during the session (see previous point), irrespective of the sport’s demands. Similarly, the value of maximal acceleration capacity, although unlikely to be reached during HIT, may eventually be considered with respect to the frequent start-
123
M. Buchheit, P. B. Laursen
and-stop requirements of HIT with short intervals [22], but, again, without direct link to the actual sport demands. Finally, while MSS is not often reached during matches [23], a faster MSS likely reduces relative neuromuscular load [15, 24], which may improve exercise tolerance and lower injury risk. Along these lines, although outside the scope of our review, the development of MSS as a training focus for team sport athletes makes logical sense, and is probably as important as acceleration capacity. Regardless, we again have an odd-shaped puzzle piece offering from Dr. Boullosa’s letter that we can’t make fit. He further states that we have a ‘‘misunderstanding [of] post-activation potentiation (PAP) after different HIT _ 2max modalities’’, where we suggest that ‘‘around vVO intensities PAP would be maximized, thus favouring a positive neuromuscular loading’’. Dr. Boullosa might have himself misunderstood our conclusions, since we were not implying a causal link between the potential PAP effect and positive neuromuscular loading. We in fact refer to ‘‘long-term structural adaptations that allow fatigue-resistance to high-speed running [25]’’ as a separate mechanism _ 2max threshold he (section 2.2.6). Indeed, the 80 % of vVO refers to for maximising PAP actually falls within the blue zone of Fig. 5 in the second part of the review (*80–85 % _ 2max, see text in section 2.2.6 [3]). While his suggesvVO tion of a likely beneficial effect of recovery intervals for neuromuscular fatigue development during HIT may be true when comparing continuous versus intermittent incremental tests, the results we show in Fig. 2b from the second part of our review suggest otherwise [3]. For instance, the repeated-sprint exercise (5 s/25 s) associated with the greater CMJ performance impairment included a longer relief interval than the HIT with short interval session (10 s/20 s), where an increase, and not a decrease, in CMJ performance was observed. This suggests that the neuromuscular responses to high-intensity exercise may reflect the combined influence of both work and relief interval characteristics, with work interval intensity the likely major contributor. Indeed, it is well-established that it is the intensity and duration of the work interval, and not the average HIT intensity, that determines the largest portion of the physiological, perceptual and performance responses to a given HIT session [26–29]. Following these lines, the mention by Dr. Boullosa of the so-called ‘‘new’’ equation proposed by Tschakert and Hofmann (already proposed by Billat nearly 15 years ago [30]) aimed at equating HIT sessions based on the average external workload, also becomes a puzzle piece that will not interlock. Dr. Boullosa ends his letter stating how ‘‘the practicality of the [HIT] programming examples provided in [our] review [are] limited without knowing the outcomes of different physical capacities’’ and that ‘‘it is necessary to study […] the
123
whole training workload [and] consider the […] other training exercises, including any form of physical activity as recently suggested [31]’’. His first comment is perplexing to us, since the four HIT programming examples we provided from different elite sport athlete programmes (Tables 4–7 of the second part of the review [3]) were shown over different training cycles, so as to illustrate how HIT manipulation can _ 2 development) be related to different physiological (e.g. VO and performance phases. Providing more detailed recommendations would, of course, be hazardous and, in fact, impossible, since there would be as many options for training programme content as there are athletes in the world (Fig. 1 of the first part of the review [2]). The idea of considering the ‘‘whole training workload’’ is reflected throughout our review, where we consistently emphasise how HIT programming needs to be considered within the context of all training content, from skill and speed/strength sessions, to _ 2 low-intensity continuous work, to threshold sessions, to VO work, to supramaximal training, to individual athlete characteristics, to recovery, etc.—this, of course, is the complex and dynamic ‘‘puzzle’’ we continually strive to solve! Reference made by Dr. Boullosa to the single study of Faude et al. [32], suggesting a greater benefit of high-volume training compared with HIT, is at odds with his aforementioned comment on the presumed importance of equated external workload amongst training sessions, as training load was in fact more than 70 % greater in the high-volume training than in the HIT group. As cited by Dr. Boullosa himself in one of his own publications [33], there are dozens of other studies showing the more favourable responses with HIT. If we were to reference a single study of best practice today, we would quote that of Stoggl and Sperlich [34], who concluded that a mixture of all types of training may be the most efficient approach. Finally, the last sentence of Dr. Boullosa’s letter, referring again to his work [31], brings up our last point, whereby throughout his letter there appears to be an undue emphasis on his own work (40 % of cited papers in his letter [1]), since the importance of actual physical activity as an interference mechanism with respect to longitudinal adaptations was suggested more than 10 years ago in adults [35] and children [36] subjected to a training intervention. While we appreciate the opportunity that Dr. Boullosa’s letter has provided to us to explain further some of the concepts within our two-part review, we hope we have made clear how his so-called forgotten pieces do not fit within a practitioner’s training programme puzzle.
References 1. Boullosa DA. The forgotten pieces of the high intensity interval training puzzle. Sports Med. 2014. doi:10.1007/s40279-014-0188-4.
Letter to the Editor 2. Buchheit M, Laursen PB. High-intensity interval training, solutions to the programming puzzle. Part I: cardiopulmonary emphasis. Sports Med. 2013;43:313–38. 3. Buchheit M, Laursen PB. High-intensity interval training, solutions to the programming puzzle. Part II: anaerobic energy, neuromuscular load and practical applications. Sports Med. 2013;43:927–54. 4. Hill DW, Rowell AL. Running velocity at VO2max. Med Sci Sports Exerc. 1996;28:114–9. 5. Midgley AW, McNaughton LR, Carroll S. Time at VO2max during intermittent treadmill running: test protocol dependent or methodological artefact? Int J Sports Med. 2007;28:934–9. 6. Buchheit M, Simpson BM, Peltola E, et al. Assessing maximal sprinting speed in highly-trained young soccer players. Int J Sports Physiol Perform. 2012;7:76–8. 7. Boullosa DA, Tuimil JL, Alegre LM, et al. Concurrent fatigue and potentiation in endurance athletes. Int J Sports Physiol Perform. 2011;6:82–93. 8. Nummela AT, Heath KA, Paavolainen LM, et al. Fatigue during a 5-km running time trial. Int J Sports Med. 2008;29:738–45. 9. Impellizzeri FM, Marcora SM, Castagna C, et al. Physiological and performance effects of generic versus specific aerobic training in soccer players. Int J Sports Med. 2006;27:483–92. 10. Buchheit M, Mendez-Villanueva A. Reliability and stability of anthropometric and performance measures in highly-trained young soccer players: effect of age and maturation. J Sports Sci. 2013;31:1332–43. 11. Buchheit M, Mendez-Villaneuva A. Supramaximal intermittent running performance in relation to age and locomotor profile in highly-trained young soccer players. J Sports Sci. 2013;31:1402–11. 12. Buchheit M, Kuitunen S, Voss SC, et al. Physiological strain associated with high-intensity hypoxic intervals in highly trained young runners. J Strength Cond Res. 2012;26:94–105. 13. Small K, McNaughton LR, Greig M, et al. Soccer fatigue, sprinting and hamstring injury risk. Int J Sports Med. 2009;30: 573–8. 14. Boullosa DA, Tuimil JL. Postactivation potentiation in distance runners after two different field running protocols. J Strength Cond Res. 2009;23:1560–5. 15. Mendez-Villanueva A, Buchheit M, Simpson BM, et al. Match play intensity distribution in youth soccer. Int J Sport Med. 2013;34:101–10. 16. Heaney N, Willey B. The efficacy of utilising the anaerobic speed reserve to prescribe supramaximal high intensity interval training with elite female hockey players. Australian Strength and Conditioning Association conference; 8–10 Nov 2013; Melbourne. 17. Buchheit M. The 30-15 Intermittent Fitness Test: accuracy for individualizing interval training of young intermittent sport players. J Strength Cond Res. 2008;22:365–74. 18. Buchheit M. Should we be recommending repeated sprints to improve repeated-sprint performance? Sports Med. 2012;42: 169–72. 19. Haugen T, Tonnessen E, Hisdal J, et al. The role and development of sprinting speed in soccer. Int J Sports Physiol Perform. Epub 2013 Aug 27. 20. Mendez-Villanueva A, Buchheit M. Football-specific fitness testing: adding value or confirming the evidence? J Sports Sci. 2013;31:1503–8.
21. Hervert SR, Sinclair K, Deakin GB. Does skill only conditioning help improve physiological and functional fitness in amateur soccer players? J Aust Strength Cond. 2013;21:34–6. 22. Dupont G, Blondel N, Berthoin S. Performance for short intermittent runs: active recovery vs. passive recovery. Eur J Appl Physiol. 2003;89:548–54. 23. Mendez-Villanueva A, Buchheit M, Simpson B, et al. Does onfield sprinting performance in young soccer players depend on how fast they can run or how fast they do run? J Strength Cond Res. 2011;25:2634–8. 24. Buchheit M, Simpson BM, Mendez-Villaneuva A. Repeated high-speed activities during youth soccer games in relation to changes in maximal sprinting and aerobic speeds. Int J sport Med. 2012;34:40–8. 25. Rusko HK, Tikkanen HO, Peltonen JE. Altitude and endurance training. J Sports Sci. 2004;(22):928–44 (discussion 945). 26. Billat LV, Slawinksi J, Bocquet V, et al. Very short (15 s-15 s) interval-training around the critical velocity allows middle-aged runners to maintain VO2 max for 14 minutes. Int J Sports Med. 2001;22:201–8. 27. Laughlin MH, Roseguini B. Mechanisms for exercise traininginduced increases in skeletal muscle blood flow capacity: differences with interval sprint training versus aerobic endurance training. J Physiol Pharmacol. 2008;59 Suppl 7:71–88. 28. Astrand I, Astrand PO, Christensen EH, et al. Intermittent muscular work. Acta Physiol Scand. 1960;48:448–53. 29. Christensen EH, Hedman R, Saltin B. Intermittent and continuous running (A further contribution to the physiology of intermittent work.). Acta Physiol Scand. 1960;50:269–86. 30. Billat LV. Interval training for performance: a scientific and empirical practice. Special recommendations for middle- and long-distance running. Part I: aerobic interval training. Sports Med. 2001;1:13–31. 31. Boullosa DA, Abreu L, Varela-Sanz A, et al. Do Olympic athletes train as in the Paleolithic era? Sports Med. 2013;43:909–17. 32. Faude O, Schnittker R, Schulte-Zurhausen R, et al. High intensity interval training vs. high-volume running training during preseason conditioning in high-level youth football: a cross-over trial. J Sports Sci. 2013;31:1441–50. 33. Tuimil JL, Boullosa DA, Fernandez-del-Olmo MA, et al. Effect of equated continuous and interval running programs on endurance performance and jump capacity. J Strength Cond Res. 2011;25:2205–11. 34. Stoggl T, Sperlich B. Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training. Front Physiol. 2014;5:33. 35. Bouchard C, Rankinen T. Individual differences in response to regular physical activity. Med Sci Sports Exerc. 2001;33: S446–51. 36. Baquet G, van Praagh E, Berthoin S. Endurance training and aerobic fitness in young people. Sports Med. 2003;33:1127–43. 37. Buchheit M. The 30-15 Intermittent Fitness Test: 10 year review. Myorobie J. 2010;(1). http://3015ift.files.wordpress.com/2013/07/ buchheit-30-15ift-10-yrs-review-2000-2010.pdf. Accessed 7 Apr 2014. 38. Bundle MW, Hoyt RW, Weyand PG. High-speed running performance: a new approach to assessment and prediction. J Appl Physiol. 2003;95:1955–62.
123
LETTER TO THE EDITOR
Dr. Boullosa’s Forgotten Pieces Don’t Fit the Puzzle Martin Buchheit • Paul B. Laursen
Springer International Publishing Switzerland 2014
We appreciate the opportunity to respond to Dr. Boullosa’s letter of concern [1] on issues brought forth in our two-part review on high-intensity interval training (HIT) [2, 3]. However, we were surprised to read the letter’s content, feeling generally that most comments were off topic, and accordingly offer little to assist the practitioner. Nevertheless, we will use this opportunity to elaborate on certain principles and in doing so outline why his so-called ‘‘forgotten pieces’’ do not fit the training programme puzzle. His first critique of our review [2] was that there was no comment as to how progressive exercise test protocol design influences the relationship between the velocity/ _ 2max) and perpower at maximal oxygen uptake (v/pVO formance. This is simply incorrect. Section 2.5 of our review extends to more than a full page of printed text describing in detail the history, theory, as well as measurement techniques practitioners can perform in both the laboratory and the field to determine appropriate values, as _ 2max well as their limitations. We state clearly how ‘‘vVO [determination] is method [4] and protocol-dependent [5]’’. It would therefore be implied that the magnitude of the _ 2max and performance would relationship between vVO comparatively be affected. We did not elaborate further on this point, as such discourse would be superfluous within the context of the review, which focused on HIT prescription, and not performance prediction. For these reasons, Dr. Boullosa’s first piece doesn’t fit.
M. Buchheit (&) Sport Science Department, Myorobie Association, 73700 Montvalezan, France e-mail: [email protected] P. B. Laursen High Performance Sport New Zealand, Auckland, New Zealand
His second critique was that ‘‘there was no reference […] to how [anaerobic speed reserve] ASR could be influenced by the method [used] for [maximal sprinting speed] MSS determination’’. While the point is valid, there are a limited number of known methods for determining MSS, and these unlikely produce differences in MSS as _ 2max or the final speed reached great as those seen with vVO during an incremental test (VIncTest) [2]. In practice, the use of a flying 10- [6] or 20-m [7, 8] time is probably the most common method of determination, although peak instantaneous speed can also be measured now with radar gun technology [9]. The difference between these methods is generally less than *2 % (personal observations), which is substantially lower than the possible *20 % difference _ 2max/VIncTest determination that can be observed for vVO [2]. Moreover, the typical error of measurement for MSS (1 %) is also clearly lower than that of VIncTest (3.5 %) [10]. Taken together, these data show that the determination of ASR is less likely to be affected by variations in _ 2max/VIncTest estimation, and explain why we MSS than vVO chose against elaborating further on this point in our review [2]. Dr. Boullosa goes on to claim that ‘‘the practicality of the 30-15 Intermittent Fitness Test (30-15IFT) for evaluating simultaneously different locomotor abilities and ASR is contradictory stricto sensu with the previous definition of ASR’’, and offers instead ‘‘a potentially simple and timesaving alternative evaluation of ASR with the recording of a maximum sprint test performed 3–5 min after an incre_ 2max determination [7]’’. The first part mental test for vVO of the comment is unclear to us, since it is now known that _ 2max/VIncTest and MSS [11]. VIFT is sensitive to both vVO The ‘‘dual sensitivity’’ of the 30-15IFT motivated our comments around the ‘‘simultaneous’’ evaluation of
123
M. Buchheit, P. B. Laursen
a
Velocity
MSS (29 km/h)
anaerobic speed reserve
VIFT (21 km/h)
vVO2max (18 km/h)
Time
b
Velocity
MSS (32 km/h)
anaerobic speed reserve
VIFT (22 km/h) vVO2max (18 km/h)
Time Fig. 1 Illustration of the importance of the anaerobic speed reserve (ASR) contribution towards reaching the final speed during the 30-15 Intermittent Fitness Test (VIFT). a Once the minimum speed required _ 2max) is reached, the additional to elicit maximal oxygen uptake (vVO energy provided during the remaining stages is derived mostly from _ 2max, the greater anaerobic sources. Therefore, for a given vVO maximal sprinting speed (MSS) and, hence, ASR (or at least the greater the proportion used), the greater the number of ‘supra_ 2max’ stages that will be completed (and the faster the VIFT). b vVO
This player having a greater ASR is able to reach, for a similar _ 2max, two further stages during the 30-15IFT (1 km/h). Since the vVO ASR (or the proportion used) also influences what can be achieved during high-intensity intermittent runs, the use of the VIFT, and not _ 2max, enables the programming of similar (anaerobic and vVO neuromuscular) training loads in workouts for each player. Adapted from Buchheit [37], with permission
different locomotor abilities. We showed that, while the first _ 2max/VIncTest, MSS is likely to be determinant of VIFT is vVO the secondary influencing variable [11]. If we take, for example, two young football players presenting with similar _ 2max/VIncTest scores, the athlete with the faster MSS also vVO has the faster VIFT (Fig. 1, adapted from Buchheit [37], with permission). The other part of Dr. Boullosa’s comment suggesting assessment of MSS following the incremental test is also at odds with the current practices that we are personally aware of, both for team sports and distance running. While standing [12] and flying [7, 8] 20-m sprint tests have been used in the literature with endurance athletes after exhaustive exercise, such procedures are problematic for assessing MSS (i.e. 10-m splits likely allow a better assessment than 20-m ones, and the fastest split is not necessarily derived from the last one [6]). Since athletes must
sprint maximally over at least 40–50 m to ensure their MSS is captured, coaches (irrespective of the sport) tend to be (in our experience) reluctant to assess MSS post-incremental test, mainly due to the increased hamstring and adductor injury risk [13]. The assessment of MSS following an incremental test is also questionable from a performance standpoint, since MSS could potentially be impaired, especially in team-sport athletes. While some endurance athletes might maintain sprinting speed [14], the magnitude of the performance decrement post-exhaustive effort is largely and inversely correlated with initial sprinting speed [8]; faster team sport players therefore would likely incur a large impairment to MSS using such an approach. Since this potentially serious effect is athlete background- and locomotor profile-dependent, it makes more sense practically to assess MSS on a separate occasion, when all athletes have
123
Letter to the Editor
_ 2max/VIncTest [11, 15]. In light of recovered from the vVO these arguments, we believe Dr. Boullosa’s second piece does not fit the puzzle. In Dr. Boullosa’s third critique, he states that ‘‘there is no actual evidence supporting the usefulness of ASR for individualizing training intensity prescription’’. While we agree that a comprehensive study comparing the acute and long-term physiological and performance responses of HIT _ 2max/VIncTest versus %ASR has yet to sessions based on vVO be published, we can provide evidence to support the use of this method to individualise HIT (Fig. 2). First, the approach is used across a considerable number of (team) sports worldwide, and has been now for more than 10 years, which is proof of its practicality, interest and
120
40
100
ASR (%)
a
35
80
Player A Player B Player C
60 40
Speed (km/h)
20 0
30 0
50
100 150 200 250 300
Time (s)
25 20 15 10 0
50
100
MAS ASR
150
200
250
Time (s)
%VIFT
Work interval duration
d
20
20
20
15
15
15 10
10
5
5
0
0
A
B
C
n
25
%
km/h
b Work interval speed c
#of work intervals
10 5 0
A
B
C
A
B
C
Fig. 2 a Predicted [38] speed/duration relationship in three soccer players with different maximal sprinting (MSS) and aerobic (MAS) speeds and peak speed reached in the 30-15 Intermittent Fitness Test (VIFT). Player A: 32, 18 and 21 km/h for MSS, MAS and VIFT, respectively; Player B: 36, 16 and 20.5 km/h; and Player C: 35, 14 and 18.5 km/h. Despite different absolute speeds at a given duration, when expressed in relation to the anaerobic speed reserve (inserted graph), these differences are eliminated. b Work interval speed in players A, B and C during high-intensity interval training (HIT) with short intervals (i.e. 15 s) prescribed at 125 % of MAS, 25 % of the anaerobic speed reserve (ASR) or 100 % of VIFT. c Work interval duration expressed as a percentage of the predicted [38] time to exhaustion at that speed. d Number of intervals required to match the predicted surpramaximal distance capacity (i.e. the distance covered under the individual curve shown in a). c and d show that using ASR or VIFT instead of MAS as the reference running speed to prescribe work interval intensity allows a better standardisation of training load during HIT in athletes with different locomotor profiles
usefulness (i.e. ‘best practice’ theory). Second, the ASR approach is taught in well-established and respected strength and conditioning courses throughout the world (e.g. France, Spain, Italy, Germany, Switzerland, USA, Australia, New Zealand), and has been the subject matter of publications by other groups (e.g. Heaney and Willey [16]). Last, as with the smaller between-athlete variations _ 2max/VIncTestin acute cardiac responses to VIFT versus vVO based HIT sessions [17], we have observed a smaller between-athlete variation in time-to-exhaustion using per_ 2max/VIncTest centage of ASR than using percentage of vVO (31 vs. 55 % during a 15 s at 95 % VIFT/15 s passive HIT, unpublished data). This clearly shows that using the entire locomotor profile (or at least VIFT) to prescribe running_ 2max, based HIT with short intervals, rather than only vVO allows the standardisation of relative exercise intensity at the individual level. The direct consequence of this intensity standardisation is that the work interval duration represents a constant fraction of the predicted time to exhaustion at this relative intensity for all athletes. Along these lines, the number of work intervals required to match the predicted supramaximal distance capacity also remains constant for all athletes (Fig. 2). Dr. Boullosa goes on to emphasise that ‘‘the improve_ 2max are independent objectives ment of both MSS and vVO that depend on the requirements of a specific sport.’’ We of course concur, as we highlighted in Fig. 1 from the first part of our review [2], where we outline how training objectives should relate to the athlete’s profile, sport and training cycle. But we did not suggest that variation in HIT formats can be used specifically to improve either MSS or _ 2max in isolation. It is clear that if the training objective vVO is to improve MSS, isolated speed/strength sessions would be recommended, and not HIT sessions [18, 19], as shown also in Fig. 1 of the first part of the review [2]. In addition, the remaining part of Dr. Boullosa’s comment, where reference is made to acceleration capacity in team sports, shows that he fails to consider separately the physiological and neuromuscular requirements of (1) a given training session aimed at improving an athlete’s physiology, and (2) competitive situations. While the principle of training specificity should not be forgotten, excessive reliance on competition-like training content (e.g. match replication) has its limitations [20, 21]. The main interest in determining ASR is to account for the athletes’ entire locomotor profile when performing a run-based HIT session at high but not maximal speed, which has implications for acute physiological and performance responses during the session (see previous point), irrespective of the sport’s demands. Similarly, the value of maximal acceleration capacity, although unlikely to be reached during HIT, may eventually be considered with respect to the frequent start-
123
M. Buchheit, P. B. Laursen
and-stop requirements of HIT with short intervals [22], but, again, without direct link to the actual sport demands. Finally, while MSS is not often reached during matches [23], a faster MSS likely reduces relative neuromuscular load [15, 24], which may improve exercise tolerance and lower injury risk. Along these lines, although outside the scope of our review, the development of MSS as a training focus for team sport athletes makes logical sense, and is probably as important as acceleration capacity. Regardless, we again have an odd-shaped puzzle piece offering from Dr. Boullosa’s letter that we can’t make fit. He further states that we have a ‘‘misunderstanding [of] post-activation potentiation (PAP) after different HIT _ 2max modalities’’, where we suggest that ‘‘around vVO intensities PAP would be maximized, thus favouring a positive neuromuscular loading’’. Dr. Boullosa might have himself misunderstood our conclusions, since we were not implying a causal link between the potential PAP effect and positive neuromuscular loading. We in fact refer to ‘‘long-term structural adaptations that allow fatigue-resistance to high-speed running [25]’’ as a separate mechanism _ 2max threshold he (section 2.2.6). Indeed, the 80 % of vVO refers to for maximising PAP actually falls within the blue zone of Fig. 5 in the second part of the review (*80–85 % _ 2max, see text in section 2.2.6 [3]). While his suggesvVO tion of a likely beneficial effect of recovery intervals for neuromuscular fatigue development during HIT may be true when comparing continuous versus intermittent incremental tests, the results we show in Fig. 2b from the second part of our review suggest otherwise [3]. For instance, the repeated-sprint exercise (5 s/25 s) associated with the greater CMJ performance impairment included a longer relief interval than the HIT with short interval session (10 s/20 s), where an increase, and not a decrease, in CMJ performance was observed. This suggests that the neuromuscular responses to high-intensity exercise may reflect the combined influence of both work and relief interval characteristics, with work interval intensity the likely major contributor. Indeed, it is well-established that it is the intensity and duration of the work interval, and not the average HIT intensity, that determines the largest portion of the physiological, perceptual and performance responses to a given HIT session [26–29]. Following these lines, the mention by Dr. Boullosa of the so-called ‘‘new’’ equation proposed by Tschakert and Hofmann (already proposed by Billat nearly 15 years ago [30]) aimed at equating HIT sessions based on the average external workload, also becomes a puzzle piece that will not interlock. Dr. Boullosa ends his letter stating how ‘‘the practicality of the [HIT] programming examples provided in [our] review [are] limited without knowing the outcomes of different physical capacities’’ and that ‘‘it is necessary to study […] the
123
whole training workload [and] consider the […] other training exercises, including any form of physical activity as recently suggested [31]’’. His first comment is perplexing to us, since the four HIT programming examples we provided from different elite sport athlete programmes (Tables 4–7 of the second part of the review [3]) were shown over different training cycles, so as to illustrate how HIT manipulation can _ 2 development) be related to different physiological (e.g. VO and performance phases. Providing more detailed recommendations would, of course, be hazardous and, in fact, impossible, since there would be as many options for training programme content as there are athletes in the world (Fig. 1 of the first part of the review [2]). The idea of considering the ‘‘whole training workload’’ is reflected throughout our review, where we consistently emphasise how HIT programming needs to be considered within the context of all training content, from skill and speed/strength sessions, to _ 2 low-intensity continuous work, to threshold sessions, to VO work, to supramaximal training, to individual athlete characteristics, to recovery, etc.—this, of course, is the complex and dynamic ‘‘puzzle’’ we continually strive to solve! Reference made by Dr. Boullosa to the single study of Faude et al. [32], suggesting a greater benefit of high-volume training compared with HIT, is at odds with his aforementioned comment on the presumed importance of equated external workload amongst training sessions, as training load was in fact more than 70 % greater in the high-volume training than in the HIT group. As cited by Dr. Boullosa himself in one of his own publications [33], there are dozens of other studies showing the more favourable responses with HIT. If we were to reference a single study of best practice today, we would quote that of Stoggl and Sperlich [34], who concluded that a mixture of all types of training may be the most efficient approach. Finally, the last sentence of Dr. Boullosa’s letter, referring again to his work [31], brings up our last point, whereby throughout his letter there appears to be an undue emphasis on his own work (40 % of cited papers in his letter [1]), since the importance of actual physical activity as an interference mechanism with respect to longitudinal adaptations was suggested more than 10 years ago in adults [35] and children [36] subjected to a training intervention. While we appreciate the opportunity that Dr. Boullosa’s letter has provided to us to explain further some of the concepts within our two-part review, we hope we have made clear how his so-called forgotten pieces do not fit within a practitioner’s training programme puzzle.
References 1. Boullosa DA. The forgotten pieces of the high intensity interval training puzzle. Sports Med. 2014. doi:10.1007/s40279-014-0188-4.
Letter to the Editor 2. Buchheit M, Laursen PB. High-intensity interval training, solutions to the programming puzzle. Part I: cardiopulmonary emphasis. Sports Med. 2013;43:313–38. 3. Buchheit M, Laursen PB. High-intensity interval training, solutions to the programming puzzle. Part II: anaerobic energy, neuromuscular load and practical applications. Sports Med. 2013;43:927–54. 4. Hill DW, Rowell AL. Running velocity at VO2max. Med Sci Sports Exerc. 1996;28:114–9. 5. Midgley AW, McNaughton LR, Carroll S. Time at VO2max during intermittent treadmill running: test protocol dependent or methodological artefact? Int J Sports Med. 2007;28:934–9. 6. Buchheit M, Simpson BM, Peltola E, et al. Assessing maximal sprinting speed in highly-trained young soccer players. Int J Sports Physiol Perform. 2012;7:76–8. 7. Boullosa DA, Tuimil JL, Alegre LM, et al. Concurrent fatigue and potentiation in endurance athletes. Int J Sports Physiol Perform. 2011;6:82–93. 8. Nummela AT, Heath KA, Paavolainen LM, et al. Fatigue during a 5-km running time trial. Int J Sports Med. 2008;29:738–45. 9. Impellizzeri FM, Marcora SM, Castagna C, et al. Physiological and performance effects of generic versus specific aerobic training in soccer players. Int J Sports Med. 2006;27:483–92. 10. Buchheit M, Mendez-Villanueva A. Reliability and stability of anthropometric and performance measures in highly-trained young soccer players: effect of age and maturation. J Sports Sci. 2013;31:1332–43. 11. Buchheit M, Mendez-Villaneuva A. Supramaximal intermittent running performance in relation to age and locomotor profile in highly-trained young soccer players. J Sports Sci. 2013;31:1402–11. 12. Buchheit M, Kuitunen S, Voss SC, et al. Physiological strain associated with high-intensity hypoxic intervals in highly trained young runners. J Strength Cond Res. 2012;26:94–105. 13. Small K, McNaughton LR, Greig M, et al. Soccer fatigue, sprinting and hamstring injury risk. Int J Sports Med. 2009;30: 573–8. 14. Boullosa DA, Tuimil JL. Postactivation potentiation in distance runners after two different field running protocols. J Strength Cond Res. 2009;23:1560–5. 15. Mendez-Villanueva A, Buchheit M, Simpson BM, et al. Match play intensity distribution in youth soccer. Int J Sport Med. 2013;34:101–10. 16. Heaney N, Willey B. The efficacy of utilising the anaerobic speed reserve to prescribe supramaximal high intensity interval training with elite female hockey players. Australian Strength and Conditioning Association conference; 8–10 Nov 2013; Melbourne. 17. Buchheit M. The 30-15 Intermittent Fitness Test: accuracy for individualizing interval training of young intermittent sport players. J Strength Cond Res. 2008;22:365–74. 18. Buchheit M. Should we be recommending repeated sprints to improve repeated-sprint performance? Sports Med. 2012;42: 169–72. 19. Haugen T, Tonnessen E, Hisdal J, et al. The role and development of sprinting speed in soccer. Int J Sports Physiol Perform. Epub 2013 Aug 27. 20. Mendez-Villanueva A, Buchheit M. Football-specific fitness testing: adding value or confirming the evidence? J Sports Sci. 2013;31:1503–8.
21. Hervert SR, Sinclair K, Deakin GB. Does skill only conditioning help improve physiological and functional fitness in amateur soccer players? J Aust Strength Cond. 2013;21:34–6. 22. Dupont G, Blondel N, Berthoin S. Performance for short intermittent runs: active recovery vs. passive recovery. Eur J Appl Physiol. 2003;89:548–54. 23. Mendez-Villanueva A, Buchheit M, Simpson B, et al. Does onfield sprinting performance in young soccer players depend on how fast they can run or how fast they do run? J Strength Cond Res. 2011;25:2634–8. 24. Buchheit M, Simpson BM, Mendez-Villaneuva A. Repeated high-speed activities during youth soccer games in relation to changes in maximal sprinting and aerobic speeds. Int J sport Med. 2012;34:40–8. 25. Rusko HK, Tikkanen HO, Peltonen JE. Altitude and endurance training. J Sports Sci. 2004;(22):928–44 (discussion 945). 26. Billat LV, Slawinksi J, Bocquet V, et al. Very short (15 s-15 s) interval-training around the critical velocity allows middle-aged runners to maintain VO2 max for 14 minutes. Int J Sports Med. 2001;22:201–8. 27. Laughlin MH, Roseguini B. Mechanisms for exercise traininginduced increases in skeletal muscle blood flow capacity: differences with interval sprint training versus aerobic endurance training. J Physiol Pharmacol. 2008;59 Suppl 7:71–88. 28. Astrand I, Astrand PO, Christensen EH, et al. Intermittent muscular work. Acta Physiol Scand. 1960;48:448–53. 29. Christensen EH, Hedman R, Saltin B. Intermittent and continuous running (A further contribution to the physiology of intermittent work.). Acta Physiol Scand. 1960;50:269–86. 30. Billat LV. Interval training for performance: a scientific and empirical practice. Special recommendations for middle- and long-distance running. Part I: aerobic interval training. Sports Med. 2001;1:13–31. 31. Boullosa DA, Abreu L, Varela-Sanz A, et al. Do Olympic athletes train as in the Paleolithic era? Sports Med. 2013;43:909–17. 32. Faude O, Schnittker R, Schulte-Zurhausen R, et al. High intensity interval training vs. high-volume running training during preseason conditioning in high-level youth football: a cross-over trial. J Sports Sci. 2013;31:1441–50. 33. Tuimil JL, Boullosa DA, Fernandez-del-Olmo MA, et al. Effect of equated continuous and interval running programs on endurance performance and jump capacity. J Strength Cond Res. 2011;25:2205–11. 34. Stoggl T, Sperlich B. Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training. Front Physiol. 2014;5:33. 35. Bouchard C, Rankinen T. Individual differences in response to regular physical activity. Med Sci Sports Exerc. 2001;33: S446–51. 36. Baquet G, van Praagh E, Berthoin S. Endurance training and aerobic fitness in young people. Sports Med. 2003;33:1127–43. 37. Buchheit M. The 30-15 Intermittent Fitness Test: 10 year review. Myorobie J. 2010;(1). http://3015ift.files.wordpress.com/2013/07/ buchheit-30-15ift-10-yrs-review-2000-2010.pdf. Accessed 7 Apr 2014. 38. Bundle MW, Hoyt RW, Weyand PG. High-speed running performance: a new approach to assessment and prediction. J Appl Physiol. 2003;95:1955–62.
123
