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Journal of Sports Sciences Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/rjsp20
Quasi-stiffness of the knee joint in flexion and extension during the golf swing a
a
a
Ahnryul Choi , Taeyong Sim & Joung Hwan Mun a
Department of Bio-Mechatronic Engineering, Sungkyunkwan University, Suwon, Republic of Korea Published online: 04 Feb 2015.
Click for updates To cite this article: Ahnryul Choi, Taeyong Sim & Joung Hwan Mun (2015): Quasi-stiffness of the knee joint in flexion and extension during the golf swing, Journal of Sports Sciences, DOI: 10.1080/02640414.2014.1003591 To link to this article: http://dx.doi.org/10.1080/02640414.2014.1003591
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Journal of Sports Sciences, 2015 http://dx.doi.org/10.1080/02640414.2014.1003591
Quasi-stiffness of the knee joint in flexion and extension during the golf swing
AHNRYUL CHOI, TAEYONG SIM & JOUNG HWAN MUN Department of Bio-Mechatronic Engineering, Sungkyunkwan University, Suwon, Republic of Korea
Downloaded by [University of Nebraska, Lincoln] at 19:56 08 April 2015
(Accepted 28 December 2014)
Abstract Biomechanical understanding of the knee joint during a golf swing is essential to improve performance and prevent injury. In this study, we quantified the flexion/extension angle and moment as the primary knee movement, and evaluated quasi-stiffness represented by moment–angle coupling in the knee joint. Eighteen skilled and 23 unskilled golfers participated in this study. Six infrared cameras and two force platforms were used to record a swing motion. The anatomical angle and moment were calculated from kinematic and kinetic models, and quasi-stiffness of the knee joint was determined as an instantaneous slope of moment–angle curves. The lead knee of the skilled group had decreased resistance duration compared with the unskilled group (P < 0.05), and the resistance duration of the lead knee was lower than that of the trail knee in the skilled group (P < 0.01). The lead knee of the skilled golfers had greater flexible excursion duration than the trail knee of the skilled golfers, and of both the lead and trail knees of the unskilled golfers. These results provide critical information for preventing knee injuries during a golf swing and developing rehabilitation strategies following surgery. Keywords: golf, knee joint, quasi-stiffness, flexion, biomechanics
1. Introduction The popularity of golf has increased continuously regardless of the age and sex. According to the World Golf Foundation, there will be more than 55 million golfers in the United States by the year 2020 (Gluck, Bendo, & Spivak, 2008). As the number of golfers increase continuously, the incidence of golf-related injury has been increasing as well (McHardy, Pollard, & Luo, 2007). The causes of the golf injuries include an overuse such as excessive play or frequent practice in professional golfers, and incorrect and poor technique in amateur golfers (Parziale & Mallon, 2006; Thériault & Lachance, 1998). Since the injury factors are different following skill levels, a comparison of swing characteristics between professional and amateur golfers may provide to better understand the golf-related injury mechanism (Zheng, Barrentine, Fleisig, & Andrews, 2008a). Knee joint injuries account for approximately 9% of total injuries in golfers (McCarroll, Rettig, & Shelbourne, 1990). It has been demonstrated that a significant load was applied to the knee joint during a golf swing compared to the activities of daily living such as gait and stair ascent (Lynn & Noffal, 2010). Internal tibia rotation relative to the femur leads to a
significant amount of moment and valgus load when the knees are slightly flexed and the feet fixed on the ground. Specifically, golfers who have strong back muscles tend to generate more rotation during a backswing, leading to greater stress on the knee joints. Additionally, compensation for tight hip muscles can change knee joint alignment. This results in even greater stress on the knee joint, and can lead to knee joint ligament and meniscus injuries. However, the exact cause of these injuries is not yet clearly established. Therefore, it is essential to examine the golf swing-specific factors related to the knee in an effort to prevent injuries and to develop rehabilitation strategies. A biomechanical evaluation of the knee joint during a golf swing can provide quantitative and objective golf swing-specific factors (Farrally et al., 2003). Knee joint kinematics and kinetics based on the motion analysis system are employed as valuable data for the improvement of swing skills by the comparison between the professional and amateur golfers, and as input of expert system for the injury prediction. In addition, the information can be used to objectively determine when golfers who underwent surgery such as anterior cruciate ligament (ACL) reconstruction and knee arthroplasty
Correspondence: Joung Hwan Mun, Department of Bio-Mechatronic Engineering, Sungkyunkwan University, Suwon, Republic of Korea. E-mail: [email protected] © 2015 Taylor & Francis
Downloaded by [University of Nebraska, Lincoln] at 19:56 08 April 2015
2
A. Choi et al.
are able to start golfing again (Gatt, Pavol, Parker, & Grabiner, 1998). There are limited previous studies, but Bechler, Jobe, Pink, Perry, and Ruwe (1995) attempted to quantify the muscle activities around the knee joint using an electromyography device in skilled golfers, while another study evaluated the effect of golf shoes and skill levels on peak knee joint load (Gatt et al., 1998). More recently, Lynn and Noffal (2010) evaluated knee moments in the frontal plane during a golf swing with an externally rotated foot position. In order to comprehend the complexities of human musculoskeletal structure, studies of quasistiffness are popular in the biomechanical fields (Butler, Crowell, & Davis, 2003). Joint quasi-stiffness, a variable that represents coordination between moment and angular displacement, is a physical quantity that reflects the neuromechanical relationship (Frigo, Crenna, & Jensen, 1996). High quasistiffness is associated with increased risk of bony injuries, and low quasi-stiffness may be related to soft tissue injuries such as the ligaments and tendons (Granata, Padua, & Wilson, 2002; Williams, McClay, & Hamill, 2001). One previous study demonstrated that quasi-stiffness can be used to analyse differences in jump motion between a normal and injured group (Hewett, Stroupe, Nance, & Noyes, 1996). There were also studies evaluating typical gait pattern of patients with Down’s syndrome (Galli, Rigoldi, Brunner, Virji-Babul, & Giorgio, 2008) and with hemiparesis (Sekiguchi, Muraki, Kuramatsu, Furusawa, & Izumi, 2012) by utilising joint quasi-stiffness. To the best of our knowledge, although quasi-stiffness is a useful biomechanical index, it has not been applied to the golf swing. Since swing mechanism and movement patterns are fundamentally different according to skill level and between the lead and trail legs (Bechler et al., 1995; Gatt et al., 1998; McCarroll et al., 1990), the biomechanical understanding of swing difference based on the quantitative quasi-stiffness can assist in preventing knee injury and in developing rehabilitation strategies. In this study, we quantified the flexion/extension angle and moment as the primary knee movement, and evaluated quasi-stiffness based on the moment–angle coupling in the knee joint. We hypothesised that there is a significant difference in quasi-stiffness between skilled and unskilled golfers, and between the lead and trail knees.
2. Methods 2.1. Participants Eighteen skilled and 23 unskilled golfers who had no history of musculoskeletal disorders or surgery within the past year participated in this study. The skilled golfers (average career 7.6 ± 3.3 years) are all
Table I. Participant characteristics (mean ± s).
Sex Age (years) Height (m) Weight (kg) Handicap (strokes)
Skilled golfers (N = 18)
Unskilled golfers (N = 23)
Male: 12, Female: 6
Male: 18, Female: 5
28.6 ± 8.3 175.6 ± 8.7 73.1 ± 11.0
Journal of Sports Sciences Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/rjsp20
Quasi-stiffness of the knee joint in flexion and extension during the golf swing a
a
a
Ahnryul Choi , Taeyong Sim & Joung Hwan Mun a
Department of Bio-Mechatronic Engineering, Sungkyunkwan University, Suwon, Republic of Korea Published online: 04 Feb 2015.
Click for updates To cite this article: Ahnryul Choi, Taeyong Sim & Joung Hwan Mun (2015): Quasi-stiffness of the knee joint in flexion and extension during the golf swing, Journal of Sports Sciences, DOI: 10.1080/02640414.2014.1003591 To link to this article: http://dx.doi.org/10.1080/02640414.2014.1003591
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Journal of Sports Sciences, 2015 http://dx.doi.org/10.1080/02640414.2014.1003591
Quasi-stiffness of the knee joint in flexion and extension during the golf swing
AHNRYUL CHOI, TAEYONG SIM & JOUNG HWAN MUN Department of Bio-Mechatronic Engineering, Sungkyunkwan University, Suwon, Republic of Korea
Downloaded by [University of Nebraska, Lincoln] at 19:56 08 April 2015
(Accepted 28 December 2014)
Abstract Biomechanical understanding of the knee joint during a golf swing is essential to improve performance and prevent injury. In this study, we quantified the flexion/extension angle and moment as the primary knee movement, and evaluated quasi-stiffness represented by moment–angle coupling in the knee joint. Eighteen skilled and 23 unskilled golfers participated in this study. Six infrared cameras and two force platforms were used to record a swing motion. The anatomical angle and moment were calculated from kinematic and kinetic models, and quasi-stiffness of the knee joint was determined as an instantaneous slope of moment–angle curves. The lead knee of the skilled group had decreased resistance duration compared with the unskilled group (P < 0.05), and the resistance duration of the lead knee was lower than that of the trail knee in the skilled group (P < 0.01). The lead knee of the skilled golfers had greater flexible excursion duration than the trail knee of the skilled golfers, and of both the lead and trail knees of the unskilled golfers. These results provide critical information for preventing knee injuries during a golf swing and developing rehabilitation strategies following surgery. Keywords: golf, knee joint, quasi-stiffness, flexion, biomechanics
1. Introduction The popularity of golf has increased continuously regardless of the age and sex. According to the World Golf Foundation, there will be more than 55 million golfers in the United States by the year 2020 (Gluck, Bendo, & Spivak, 2008). As the number of golfers increase continuously, the incidence of golf-related injury has been increasing as well (McHardy, Pollard, & Luo, 2007). The causes of the golf injuries include an overuse such as excessive play or frequent practice in professional golfers, and incorrect and poor technique in amateur golfers (Parziale & Mallon, 2006; Thériault & Lachance, 1998). Since the injury factors are different following skill levels, a comparison of swing characteristics between professional and amateur golfers may provide to better understand the golf-related injury mechanism (Zheng, Barrentine, Fleisig, & Andrews, 2008a). Knee joint injuries account for approximately 9% of total injuries in golfers (McCarroll, Rettig, & Shelbourne, 1990). It has been demonstrated that a significant load was applied to the knee joint during a golf swing compared to the activities of daily living such as gait and stair ascent (Lynn & Noffal, 2010). Internal tibia rotation relative to the femur leads to a
significant amount of moment and valgus load when the knees are slightly flexed and the feet fixed on the ground. Specifically, golfers who have strong back muscles tend to generate more rotation during a backswing, leading to greater stress on the knee joints. Additionally, compensation for tight hip muscles can change knee joint alignment. This results in even greater stress on the knee joint, and can lead to knee joint ligament and meniscus injuries. However, the exact cause of these injuries is not yet clearly established. Therefore, it is essential to examine the golf swing-specific factors related to the knee in an effort to prevent injuries and to develop rehabilitation strategies. A biomechanical evaluation of the knee joint during a golf swing can provide quantitative and objective golf swing-specific factors (Farrally et al., 2003). Knee joint kinematics and kinetics based on the motion analysis system are employed as valuable data for the improvement of swing skills by the comparison between the professional and amateur golfers, and as input of expert system for the injury prediction. In addition, the information can be used to objectively determine when golfers who underwent surgery such as anterior cruciate ligament (ACL) reconstruction and knee arthroplasty
Correspondence: Joung Hwan Mun, Department of Bio-Mechatronic Engineering, Sungkyunkwan University, Suwon, Republic of Korea. E-mail: [email protected] © 2015 Taylor & Francis
Downloaded by [University of Nebraska, Lincoln] at 19:56 08 April 2015
2
A. Choi et al.
are able to start golfing again (Gatt, Pavol, Parker, & Grabiner, 1998). There are limited previous studies, but Bechler, Jobe, Pink, Perry, and Ruwe (1995) attempted to quantify the muscle activities around the knee joint using an electromyography device in skilled golfers, while another study evaluated the effect of golf shoes and skill levels on peak knee joint load (Gatt et al., 1998). More recently, Lynn and Noffal (2010) evaluated knee moments in the frontal plane during a golf swing with an externally rotated foot position. In order to comprehend the complexities of human musculoskeletal structure, studies of quasistiffness are popular in the biomechanical fields (Butler, Crowell, & Davis, 2003). Joint quasi-stiffness, a variable that represents coordination between moment and angular displacement, is a physical quantity that reflects the neuromechanical relationship (Frigo, Crenna, & Jensen, 1996). High quasistiffness is associated with increased risk of bony injuries, and low quasi-stiffness may be related to soft tissue injuries such as the ligaments and tendons (Granata, Padua, & Wilson, 2002; Williams, McClay, & Hamill, 2001). One previous study demonstrated that quasi-stiffness can be used to analyse differences in jump motion between a normal and injured group (Hewett, Stroupe, Nance, & Noyes, 1996). There were also studies evaluating typical gait pattern of patients with Down’s syndrome (Galli, Rigoldi, Brunner, Virji-Babul, & Giorgio, 2008) and with hemiparesis (Sekiguchi, Muraki, Kuramatsu, Furusawa, & Izumi, 2012) by utilising joint quasi-stiffness. To the best of our knowledge, although quasi-stiffness is a useful biomechanical index, it has not been applied to the golf swing. Since swing mechanism and movement patterns are fundamentally different according to skill level and between the lead and trail legs (Bechler et al., 1995; Gatt et al., 1998; McCarroll et al., 1990), the biomechanical understanding of swing difference based on the quantitative quasi-stiffness can assist in preventing knee injury and in developing rehabilitation strategies. In this study, we quantified the flexion/extension angle and moment as the primary knee movement, and evaluated quasi-stiffness based on the moment–angle coupling in the knee joint. We hypothesised that there is a significant difference in quasi-stiffness between skilled and unskilled golfers, and between the lead and trail knees.
2. Methods 2.1. Participants Eighteen skilled and 23 unskilled golfers who had no history of musculoskeletal disorders or surgery within the past year participated in this study. The skilled golfers (average career 7.6 ± 3.3 years) are all
Table I. Participant characteristics (mean ± s).
Sex Age (years) Height (m) Weight (kg) Handicap (strokes)
Skilled golfers (N = 18)
Unskilled golfers (N = 23)
Male: 12, Female: 6
Male: 18, Female: 5
28.6 ± 8.3 175.6 ± 8.7 73.1 ± 11.0
