Strength, flexibility, and balance characteristics of highly proficient golfers

Despite the emergence of golf-specific training programs and training aids, relatively little research has been conducted examining the physical characteristics that are important to golf performance. We studied the strength, flexibility, and balance characteristics of golfers across 3 proficiency levels based on handicap index (HCP) (<0, 1-9, and 10-20) to determine the physical characteristics unique to highly proficient golfers. A total of 257 (age: 45.5 +/- 12.8 years, height: 180.6 +/- 6.5 cm, weight: 87.9 +/- 12.6 kg) healthy, male golfers participated in the study. Testing included an assessment of strength (torso, shoulder, and hip), flexibility (torso, shoulder, and hip), and single-leg balance. Golfers in the highest proficiency group (HCP < 0) had significantly (p < 0.05) greater hip strength, torso strength, shoulder strength, shoulder flexibility, hip flexibility, torso flexibility, and balance (eyes open) than golfers in the lowest proficiency group (HCP 10-20). The results of this study demonstrate that better golfers possess unique physical characteristics that are important to greater proficiency. These characteristics have also been demonstrated to be modifiable through golf-specific training programs.     

Effects of an 18-week strength training program on low-handicap golfers' performance

The purpose of this study was to determine the effects of an 18-week strength training program on variables related to low-handicap golfers' performance. Ten right-handed male golfers, reporting a handicap of 5 or less, were randomly divided into two groups: the control group (CG) (N = 5, age: 23.9 ± 6.7 years) and the treatment group (TG) (N = 5, age: 24.2 ± 5.4 years). CG players followed the standard physical conditioning program for golf, which was partially modified for the TG. The TG participated in an 18-week strength training program divided into three parts: maximal strength training including weightlifting exercises (2 days a week for 6 weeks), explosive strength training with combined weights and plyometric exercises (2 days a week for 6 weeks), and golf-specific strength training, including swings with a weighted club and accelerated swings with an acceleration tubing system (3 days a week for 6 weeks). Body mass, body fat, muscle mass, jumping ability, isometric grip strength, maximal strength (RM), ball speed, and golf club mean acceleration were measured on five separate occasions. The TG demonstrated significant increases (p < 0.05) in maximal and explosive strength after 6 weeks of training and in driving performance after 12 weeks. These improvements remained unaltered during the 6-week golf-specific training period and even during a 5-week detraining period. It may be concluded that an 18-week strength training program can improve maximal and explosive strength and these increases can be transferred to driving performance; however, golfers need time to transfer the gains.     

Effect of an 8-week combined weights and plyometrics training program on golf drive performance

The purpose of this study was to determine the effect of a combined weights and plyometrics program on golf drive performance. Eleven male golfers' full golf swing was analyzed for club head speed (CS) and driving distance (DD) before and after an 8-week training program. The control group (n = 5) continued their normal training, while the experimental group (n = 6) performed 2 sessions per week of weight training and plyometrics. Controls showed no significant (p > or = 0.05) changes, while experimental subjects showed a significant increase (p < or = 0.05) in CS and DD. The changes in golf drive performance were attributed to an increase in muscular force and an improvement in the sequential acceleration of body parts contributing to a greater final velocity being applied to the ball. It was concluded that specific combined weights and plyometrics training can help increase CS and DD in club golfers.     

Rotational biomechanics of the elite golf swing: benchmarks for amateurs

The purpose of this study was to determine biomechanical factors that may influence golf swing power generation. Three-dimensional kinematics and kinetics were examined in 10 professional and 5 amateur male golfers. Upper-torso rotation, pelvic rotation, X-factor (relative hip-shoulder rotation), O-factor (pelvic obliquity), S-factor (shoulder obliquity), and normalized free moment were assessed in relation to clubhead speed at impact (CSI). Among professional golfers, results revealed that peak free moment per kilogram, peak X-factor, and peak S-factor were highly consistent, with coefficients of variation of 6.8%, 7.4%, and 8.4%, respectively. Downswing was initiated by reversal of pelvic rotation, followed by reversal of upper-torso rotation. Peak X-factor preceded peak free moment in all swings for all golfers, and occurred during initial downswing. Peak free moment per kilogram, X-factor at impact, peak X-factor, and peak upper-torso rotation were highly correlated to CSI (median correlation coefficients of 0.943, 0.943, 0.900, and 0.900, respectively). Benchmark curves revealed kinematic and kinetic temporal and spatial differences of amateurs compared with professional golfers. For amateurs, the number of factors that fell outside 1-2 standard deviations of professional means increased with handicap. This study identified biomechanical factors highly correlated to golf swing power generation and may provide a basis for strategic training and injury prevention.     

Effect of torso rotational strength on angular hip, angular shoulder, and linear bat velocities of high school baseball players

This investigation examined the effect of torso rotational strength on angular hip (AHV), angular shoulder (ASV), linear bat-end (BEV), and hand velocities (HV) and 3 repetition maximum (RM) torso rotational and sequential hip-torso-arm rotational strength (medicine ball hitter's throw) in high school baseball players (age 15.4 +/- 1.2 y). Participants were randomly assigned to 1 of 2 training groups. Group 1 (n = 24) and group 2 (n = 25) both performed a stepwise periodized resistance exercise program and took 100 swings a day, 3 days a week, for 12 weeks with their normal game bat. Group 2 performed additional rotational and full-body medicine ball exercises 3 days a week for 12 weeks. A 3RM parallel squat and bench press were measured at 0 and after 4, 8, and 12 weeks. Participants were pre- and posttested for 3RM dominant and nondominant torso rotational strength and medicine ball hitter's throw. Angular hip velocities, ASV, BEV, and HV were recorded pre- and posttraining by a motion capture system that identified and digitally processed reflective markers attached to each participant's bat and body. Groups 1 and 2 increased (p < or = 0.05) BEV (3.6 and 6.4%), HV (2.6 and 3.6%), 3RM dominant (10.5 and 17.1%) and nondominant (10.2 and 18.3%) torso rotational strength, and medicine ball hitter's throw (3.0 and 10.6%) after 12 weeks. Group 2 increased AHV (6.8%) and ASV (8.8%). Group 2 showed greater improvements in BEV, AHV, ASV, 3RM dominant and nondominant torso rotational strength, and medicine ball hitter's throw than group 1. Groups 1 and 2 increased predicted 1RM parallel squat (29.7 and 26.7%) and bench press (17.2 and 16.7%) strength after 12 weeks. These data indicate that performing additional rotational medicine ball exercises 2 days a week for 12 weeks statistically improves baseball performance variables.     

Electromyography variables during the golf swing: A literature review

The aim of the study was to review systematically the literature available on electromyographic (EMG) variables of the golf swing. From the 19 studies found, a high variety of EMG methodologies were reported. With respect to EMG intensity, the right erector spinae seems to be highly activated, especially during the acceleration phase, whereas the oblique abdominal muscles showed moderate to low levels of activation. The pectoralis major, subscapularis and latissimus dorsi muscles of both sides showed their peak activity during the acceleration phase. High muscle activity was found in the forearm muscles, especially in the wrist flexor muscles demonstrating activity levels above the maximal voluntary contraction. In the lower limb higher muscle activity of the trail side was found. There is no consensus on the influence of the golf club used on the neuromuscular patterns described. Furthermore, there is a lack of studies on average golf players, since most studies were executed on professional or low handicap golfers.Further EMG studies are needed, especially on lower limb muscles, to describe golf swing muscle activation patterns and to evaluate timing parameters to characterize neuromuscular patterns responsible for an efficient movement with lowest risk for injury.     

Effects of physical conditioning on intercollegiate golfer performance

This investigation was conducted to determine the effects of a physical conditioning program on clubhead speed, consistency, and putting distance control in 10 men and 6 women National Collegiate Athletic Association Division I golfers. Supervised strength, power, and flexibility training was performed 3 times per week for 11 weeks. Performance tests were conducted before and after the training period. Significant (p < 0.05) increases were noted for all strength, power, and flexibility tests from pre- to posttraining of between 7.3 and 19.9%. Clubhead speed increased significantly (1.6%), equating to approximately a 4.9-m increase in driving distance. Putting distance control significantly improved for the men-only group (29.6%), whereas there was no significant difference in putting distance control for the total and women-only groups. Eleven weeks of golf-specific physical conditioning increased clubhead speed without a negative effect on consistency or putting distance control in intercollegiate men and women golfers.     

Multifunctional Sensor Based on Translational‐Rotary Triboelectric Nanogenerator

Triboelectric nanogenerators with a large number of desirable advantages, such as flexibility, light weight, and easy integration, are unique for sensor design. In this paper, based on the triboelectric nanogenerator (TENG), a cylindrical self‐powered multifunctional sensor (MS) with a translational‐rotary magnetic mechanism is proposed, which has the capacity to detect acceleration, force, and rotational parameters. The MS can transform a translational motion into a swing motion or a multicircle rotational motion of a low damping magnetic cylinder around a friction layer and hence drives the TENG to generate voltages output. For enhancing the output performance of the TENG, an electrode material with small work function, low resistance, and suitable surface topography is the best choice. According to the structure characteristic of the translational‐rotary magnetic mechanism, the MS can easily respond to a weak striking and can be used to measure the rotational parameters without the need of coaxial installation. Based on the MS, some applications are established, for example measuring the punch acceleration of a boxer, the hitting force and swing angle of golf club, which demonstrate the feasibility and efficiency of the MS and exhibit that the MS could find applications in sports.     

Thorax and pelvis kinematics during the downswing of male and female skilled golfers

Thorax and pelvis motion during the golf swing have most frequently been described for male golfers at discrete points during the swing, such as top of backswing (TBS) and ball contact (BC). Less is known about the continual motion and coordination of the thorax and pelvis throughout the downswing for either male or female golfers. The purpose of this study was to present detailed 3D kinematic profiles of thorax and pelvis motion during the downswing, and to determine if differences in kinematics exist between male and female skilled golfers. Thorax and pelvis data were collected from 19 male (26±7 years) and 19 female (25±7 years) skilled golfers (handicap ≤4) using an optical motion analysis system. 3D segment position, orientation and angular velocity were calculated, along with phase plane trajectories and thorax–pelvis separation angles. At BC males had greater pelvis posterior tilt, greater pelvis and thorax lateral tilt to the right, and less pelvis and thorax axial rotation to the left compared to females. Males achieved greater peak thorax and pelvis angular velocity, and angular velocity at BC, in the anterior–posterior and lateral tilt directions. Phase plane trajectories revealed that males and females had similar thorax lateral tilt and anterior–posterior tilt angular velocity–displacement relationships at TBS, yet by BC males had greater tilt angles and velocities compared to females. Collectively, the results suggest that male and female skilled golfers have different kinematics for thorax and pelvis motion, predominantly for lateral and anterior–posterior tilt. What might be considered optimal swing characteristics for male golfers should not be generalized to female golfers.     

Functional training improves club head speed and functional fitness in older golfers

Functional training programs have been used in a variety of rehabilitation settings with documented success. Based on that success, the concept of functional training has gained popularity in applied fitness settings to enhance sport performance. However, there has been little or no research studying the efficacy of functional training programs on the improvement of sport performance or functional fitness. Thus, it was the purpose of this study to determine the effect of a progressive functional training program on club head speed and functional fitness in older male golfers. Eighteen male golfers (age: 70.7 +/- 9.1 [SD] years) were randomly assigned to an exercise (N = 11) or control (N = 7) group. The exercise group participated in an 8-week progressive functional training program including flexibility exercises, core stability exercises, balance exercises, and resistance exercises. Pre- and postmeasurements included club head speed of a driver by radar (exercise and Control) and Fullerton Senior Fitness Test measurements (exercise only). One-way analysis of covariance was performed on club head speed measurements using pretest measurements as the covariate. Paired t-tests were performed to analyze Senior Fitness Test variables. After the intervention, maximal club head speed increased in the exercise group (127.3 +/- 13.4 to 133.6 +/- 14.2 km x hr(-1)) compared with the control group (134.5 +/- 14.6 to 133.3 +/- 11.2 km x hr(-1); p < 0.05). Additionally, improvements (p < 0.05) were detected for most Senior Fitness Test variables in the exercise group. In summary, this functional training program resulted in significant improvements in club head speed and several components of functional fitness. Future research should continue to examine the effect of functional training programs on sport performance and functional fitness in older adults.     

The relationship between isometric force-time curve characteristics and club head speed in recreational golfers

ABSTRACT: Leary, BK, Statler, J, Hopkins, B, Fitzwater, R, Kesling, T, Lyon, J, Phillips, B, Bryner, RW, Cormie, P, and Haff, GG. The relationship between isometric force-time curve characteristics and club head speed in recreational golfers. J Strength Cond Res 26(10): 2685-2697, 2012-The primary purpose of the present investigation was to examine the relationships between club head speed, isometric midthigh pull performance, and vertical jump performance in a cohort of recreational golfers. Twelve recreational golfers (age, 20.4 ± 1.0 years; weight, 77.0 ± 9.8 kg; height, 177.8 ± 6.3 cm; body fat, 17.1 ± 7.6%; handicap, 14.5 ± 7.3; experience, 8.9 ± 3.6 years) completed 3 testing sessions: (a) familiarization session and body composition measurements; (b) measurement of force-time curves in the isometric midthigh pull, countermovement, and static vertical jump (SJ); and (c) measurement of club head speed. During sessions 1 and 2, subjects performed 5 countermovement jumps, 5 SJ, and 2 isometric midthigh pulls. Isometric peak force was measured at 30, 50, 90, 100, 200, and 250 milliseconds. Rate of force development was measured among 0-30, 0-50, 0-90, 0-100, 0-200, and 0-250 milliseconds. Peak rate of force development was determined as the highest value in a 10-millisecond sampling windows. During session 3, subjects performed 10 maximal golf swings with a driver to measure club head speed; peak and average club head speed were analyzed across the 10 swings. Golf handicap was moderately correlated with average (r = -0.52, p = 0.04) and maximal club head speed (r = -0.45, p = 0.07). Force at 150 milliseconds during the isomeric midthigh pull test was moderately correlated with average (r = 0.46, p = 0.07) and maximal club head speed (r = 0.47, p = 0.06). Moderate correlations were also found between the rate of force development from 0 to 150 milliseconds and average (r = 0.38, p = 0.11) and maximal club head speed (r = 0.36, p = 0.12). The present findings suggest that the ability to exhibit high ground reaction forces in time frames <200 milliseconds are related to high club head speeds.     

The role of the shaft in the golf swing.

Current marketing of golf clubs places great emphasis on the importance of the correct choice of shaft in relation to the golfer. The design of shafts is based on a body of received wisdom for which there appears to be little in the way of hard evidence, either of a theoretical or experimental nature. In this paper the behaviour of the shaft in the golf swing is investigated using a suitable dynamic computer simulation and by making direct strain gauge measurements on the shaft during actual golf swings. The conclusion is, contrary to popular belief, that shaft bending flexibility plays a minor dynamic role in the golf swing and that the conventional tests associated with shaft specification are peculiarly inappropriate to the swing dynamics; other tests are proposed. A concomitant conclusion is that it should be difficult for the golfer to actually identify shaft flexibility. It is found that if golfers are asked to hit golf balls with sets of clubs having different shafts but identical swingweights the success rate in identifying the shaft is surprisingly low.     

Relationship between functional movement screen and athletic performance

Parchmann, CJ and McBride, JM. Relationship between functional movement screen and athletic performance. J Strength Cond Res 25(12): 3378-3384, 2011-Tests such as the functional movement screen (FMS) and maximal strength (repetition maximum strength [1RM]) have been theorized to assist in predicting athletic performance capabilities. Some data exist concerning 1RM and athletic performance, but very limited data exist concerning the potential ability of FMS to assess athletic performance. The purpose of this investigation was to determine if FMS scores or 1RM is related to athletic performance, specifically in Division I golfers in terms of sprint times, vertical jump (VJ) height, agility T-test times, and club head velocity. Twenty-five National Collegiate Athletic Association Division I golfers (15 men, age = 20.0 ± 1.2 years, height = 176.8 ± 5.6 cm, body mass = 76.5 ± 13.4 kg, squat 1RM = 97.1 ± 21.0 kg) (10 women, age = 20.5 ± 0.8 years, height = 167.0 ± 5.6 cm, body mass = 70.7 ± 21.5 kg, squat 1RM = 50.3 ± 16.6) performed an FMS, 1RM testing, and field tests common in assessing athletic performance. Athletic performance tests included 10- and 20-m sprint time, VJ height, agility T-test time, and club head velocity. Strength testing included a 1RM back squat. Data for 1RM testing were normalized to body mass for comparisons. Correlations were determined between FMS, 1RMs, and athletic performance tests using Pearson product correlation coefficients (p ≤ 0.05). No significant correlations existed between FMS and 10-m sprint time (r = -0.136), 20-m sprint time (r = -0.107), VJ height (r = 0.249), agility T-test time (r = -0.146), and club head velocity (r = -0.064). The 1RM in the squat was significantly correlated to 10-m sprint time (r = -0.812), 20-m sprint time (r = -0.872), VJ height (r = 0.869), agility T-test time (r = -0.758), and club head velocity (r = 0.805). The lack of relationship suggests that FMS is not an adequate field test and does not relate to any aspect of athletic performance. Based on the data from this investigation, 1RM squat strength appears to be a good indicator of athletic performance.     

The relation between anthropometric and physiological variables and bat velocity of high-school baseball players before and after 12 weeks of training

The purpose of this article was to investigate the relation between anthropometric and physiological variables to linear bat swing velocity (BV) of 2 groups of high-school baseball players before and after completing a 12-week periodized resistance exercise program. Participants were randomly assigned to 1 of 2 training groups using a stratified sampling technique. Group 1 (n = 24) and group 2 (n = 25) both performed a stepwise periodized resistance exercise program and took 100 swings a day, 3 d·wk-1, for 12 weeks with their normal game bat. Group 2 performed additional rotational and full-body medicine ball exercises 3 d·wk-1 for 12 weeks. Fourteen variables were measured or calculated before and after 12 weeks of training. Anthropometric and physiological variables tested were height, body mass, percent body fat, lean body mass (LBM), dominant torso rotational strength (DTRS) and nondominant torso rotational strength (NDTRS), sequential hip-torso-arm rotational strength measured by a medicine ball hitter's throw (MBHT), estimated 1 repetition maximum parallel squat (PS) and bench press (BP), vertical jump (VJ), estimated peak power, angular hip velocity (AHV), and angular shoulder velocity (ASV). The baseball-specific skill of linear BV was also measured. Statistical analysis indicated a significant moderately high positive relationship (p ≤ 0.05) between prelinear BV and pre-NDTRS for group 1, pre-LBM, DTRS, NDTRS, peak power, and ASV for group 2; moderate positive relationship between prelinear BV and preheight, LBM, DTRS, peak power, BP, PS, and ASV for group 1, preheight, body mass, MBHT, BP, and PS for group 2. Significantly high positive relationships were indicated between postlinear BV and post-NDTRS for group 1, post-DTRS and NDTRS for group 2; moderately high positive relationships between postlinear BV and post-LBM, DTRS, peak power, BP, and PS for group 1, postheight, LBM, VJ, peak power for group 2; moderate positive relationships between postlinear BV and postheight, body mass, MBHT, and VJ for group 1, postbody mass, MBHT, BP, PS, and ASV for group 2. Significantly low positive relationships were indicated between prelinear BV and prebody mass, MBHT, and VJ for group 1, pre-VJ and AHV for group 2; postlinear BV and post-AHV for group 2. These data show that significant relationships do exist between height, body mass, LBM, rotational power, rotational strength, lower body power, upper and lower body strength, AHV, and ASV to linear BV of high-school baseball players. Strength coaches may want to consider using this information when designing a resistance training program for high-school baseball players. Those recruiting or scouting baseball players may want to use this information to further develop ways of identifying talented players. However, one should be cautious when interpreting this information when designing strength training programs for high-school baseball players to increase linear BV.     

Effect of twelve weeks of medicine ball training on high school baseball players

This study examined the effect of 12 weeks of medicine ball training on high school baseball players. Forty-nine baseball players (age 15.4 +/- 1.2 years) were randomly assigned using a stratified sampling technique to 1 of 2 groups. Group 1 (n = 24) and group 2 (n = 25) performed the same full-body resistance exercises according to a stepwise periodized model and took 100 bat swings a day, 3 days per week, with their normal game bat for 12 weeks. Group 2 performed additional rotational and full-body medicine ball exercises 3 days per week for 12 weeks. Pre- and post-testing consisted of a 3 repetition maximum (RM) dominant and nondominant torso rotational strength and sequential hip-torso-arm rotational strength (medicine ball hitter's throw). A 3RM parallel squat and bench press were measured at 0 and after 4, 8, and 12 weeks of training. Although both groups made statistically significant increases (p < or = 0.05) in dominant (10.5 vs. 17.1%) and nondominant (10.2 vs. 18.3%) torso rotational strength and the medicine ball hitter's throw (3.0 vs. 10.6%), group 2 showed significantly greater increases in all 3 variables than group 1. Furthermore, both groups made significant increases in predicted 1RM parallel squat and bench press after 4, 8, and 12 weeks of training; however, there were no differences between groups. These data indicate that performing a 12-week medicine ball training program in addition to a stepwise periodized resistance training program with bat swings provided greater sport-specific training improvements in torso rotational and sequential hip-torso-arm rotational strength for high school baseball players.     

The analysis of golf swing as a kinematic chain using dual Euler angle algorithm

The manner in which anatomical rotation from an individual segment contributes to the position and velocity of the endpoint can be informative in the arena of many athletic events whose goals are to attain the maximal velocity of the most distal segment. This study presents a new method of velocity analysis using dual Euler angles and its application in studying rotational contribution from upper extremity segments to club head speed during a golf swing. Dual Euler angle describes 3D movement as a series of ordered screw motions about each orthogonal axis in a streamlined matrix form-the dual transformation matrix- and allows the translation and rotation component to be described in the same moving frame. Applying this method in biomechanics is a novel idea and the authors have previously applied the methodology to clinical studies on its use in displacement analysis. The focus of this paper is velocity analysis and applications in sports biomechanics. In this study, electrogoniometers (Biometrics, UK) with a frequency of 1000 Hz were attached to a subject during the execution of the swing to obtain the joint angles throughout the motion. The velocity of the club head was then analyzed using the dual velocity which specifies the velocity distribution of a rigid body in screw motion at any point in time as the dual vector. The contributions of each segment to the club-head velocity were also compared. In order to evaluate this method, the calculated position and velocity of the club head were compared to the values obtained from video image analysis. The results indicated that there is good agreement between calculated values and video data, suggesting the suitability of using the Dual Euler method in analyzing a kinematic chain motion.     

Latent effect of passive static stretching on driver clubhead speed, distance, accuracy, and consistent ball contact in young male competitive golfers

This investigation was conducted to determine the effect of 2 different warm-up treatments over time on driver clubhead speed, distance, accuracy, and consistent ball contact in young male competitive golfers. Two supervised warm-up treatments, an active dynamic warm-up with golf clubs (AD) and a 20-minute total body passive static stretching routine plus an identical AD warm-up (PSS), were applied before each performance testing session using a counterbalanced design on nonconsecutive days. Immediately after the AD treatment, subjects were instructed to hit 3 full swing golf shots with their driver with 1-minute rest between trials. Immediately after the PSS treatment, subjects were instructed to hit 3 full-swing golf shots with their driver at t0 and thereafter at t15, t30, t45, and t60 minutes with 1-minute rest between swing trials to determine any latent effects of PSS on golf driver performance measures. Results of paired t-tests revealed significant (p < 0.05) decreases in clubhead speed at t0 (-4.92%), t15 (-2.59%), and t30 (-2.19%) but not at t45 (-0.95) or t60 (-0.99). Significant differences were also observed in distance at t0 (-7.26%), t15 (-5.19%), t30 (-5.47%), t45 (-3.30%), and t60 (-3.53%). Accuracy was significantly impaired at t0 (61.99%), t15 (58.78%), t30 (59.46%), and t45 (61.32%) but not at t60 (36.82%). Finally, consistent ball contact was significantly reduced at t0 (-31.29%), t15 (-31.29%), t30 (-23.56%), t45 (-27.49%), and t60 (-15.70%). Plausible explanations for observed performance decrements include a more compliant muscle-tendon unit (MTU) and an altered neurological state because of the PSS treatment. Further, the findings of this study provide evidence supporting the theory that the mechanical properties of the MTU may recover at a faster rate than any associated neurological changes. The results of this inquiry strongly suggest that a total-body passive static stretching routine should be avoided before practice or competition in favor of a gradual AD. Athletes with poor mechanics because of lack of flexibility should perform these exercises after a conditioning session, practice, or competition.     

Effect of acute mild dehydration on cognitive-motor performance in golf

ABSTRACT: Smith, MF, Newell, AJ, and Baker, MA. Effect of acute mild dehydration on cognitive-motor performance in golf. J Strength Cond Res 26(11): 3075-3080, 2012-Whether mild dehydration (-1 to 3% body mass change [ΔBM]) impairs neurophysiological function during sport-specific cognitive-motor performance has yet to be fully elucidated. To investigate this within a golfing context, 7 low-handicap players (age: 21 ± 1.1 years; mass: 76.1 ± 11.8 kg; stature: 1.77 ± 0.07 m; handicap: 3.0 ± 1.2) completed a golf-specific motor and cognitive performance task in a euhydrated condition (EC) and dehydrated condition (DC) (randomized counterbalanced design; 7-day interval). Dehydration was controlled using a previously effective 12-hour fluid restriction, monitored through ΔBM and urine color assessment (UCOL). Mild dehydration reduced the mean BM by 1.5 ± 0.5% (p = 0.01), with UCOL increasing from 2 (EC) to 4 (DC) (p = 0.02). Mild dehydration significantly impaired motor performance, expressed as shot distance (114.6 vs. 128.6 m; p < 0.001) and off-target accuracy (7.9 vs. 4.1 m; p = 0.001). Cognitive performance, expressed as the mean error in distance judgment to target increased from 4.1 ± 3.0 m (EC) to 8.8 ± 4.7 m (DC) (p < 0.001). The findings support those of previous research that indicates mild dehydration (-1 to 2% ΔBM) significantly impairs cognitive-motor task performance. This study is the first to show that mild dehydration can impair distance, accuracy, and distance judgment during golf performance.     

A comparison of lower-body flexibility, strength, and knee stability between karate athletes and active controls

The purposes of this study were to compare the lower-body flexibility, strength, and knee stability of karate athletes against that of non-karate controls and to determine whether regular karate training results in adaptations that may result in an increased risk for knee injury. Flexibility measurements included knee flexion and extension, hip flexion and extension, hip internal and external rotation, and foot inversion and eversion. Nine karate athletes (4 women and 5 men, age = 24.3 +/- 6.7 years) and 15 active, non-karate controls (7 women and 8 men, age = 22.1 +/- 3.2 years) participated. No subjects reported recent knee surgery or chronic or acute knee pain. Concentric quadriceps and hamstrings strength and endurance were measured using a Biodex II isokinetic dynamometer at 60 degrees .s(-1) and 180 degrees .s(-1). Eccentric strength was measured at 150 degrees .s(-1) and 250 ft-lb (339 N.m). Knee stability was measured via varus and valgus stress and anterior drawer testing. Karate athletes demonstrated a significantly greater right hip flexion (p 相似文献   

Physiological and performance characteristics of adolescent club volleyball players

The objective of this investigation was to examine the physical and performance characteristics of adolescent club volleyball players. Twenty-nine adolescent girls, aged 12 to 17 years (14.31 +/- 1.37) were participants in this investigation. All athletes were members of a competitive volleyball club. The following group values were obtained: height (HT) = 1.69 +/- 0.08 m, weight (WT) = 59.6 +/- 8.2 kg, body fat percentage (BF%) = 20.9 +/- 4.5, lean body mass (LBM) = 46.7 +/- 4.9 kg, modified sit-and-reach (MSR) = 38.7 +/- 7.1 cm, shoulder rotation (SR) = 29.4 +/- 5.6 cm, isometric hand grip (IHG) = 34.5 +/- 5.5 kg, isometric leg strength (ILS) = 77.4 +/- 18.1 kg, vertical jump (VJ) = 35.5 +/- 6.2 cm, standing broad jump (SBJ) =178.8 +/- 20.3 cm, 1-minute sit-ups (SU) = 47.0 +/- 6.7, T-test (TT) = 11.2 +/- 0.8 seconds., shuttle test (SHT) = 9.7 +/- 0.4 seconds, stork stand (SS) = 8.1 +/- 4.1 seconds, serving velocity (SVV) =16.1 +/- 4.5 m.s(-1), and spiking velocity (SKV) = 16.9 +/- 2.4 m.s(-1). For purposes of analysis, players were divided into 2 age groups: 12 to 14 years (group A) and 15 to 17 years (group B). Significant differences (p < 0.05) were found between age groups for the following values: HT, WT, LBM, IHG, ILS, SBJ, and SVV. Values for group B were greater for each variable. Significant correlations include age and IHG (r = 0.75), age and ILS (r = 0.51), age and SBJ (r = 0.67), age and SVV (r = 0.71), LBM and IHG (r = 0.90), LBM and ILS (r = 0.62), LBM and SVV (r = 0.58), SVV and IHG (r = 0.60), and SKV and SS (r = 0.60). Our results suggest that age, experience, LBM, shoulder, hip, and thigh girths, strength, and balance are key physical performance characteristics of adolescent girls who play volleyball. Potentially, this type of information will allow coaches and athletes to identify physical and performance data specific to age groups for purposes of evaluation and player development.