Shoe choice may affect fencing lunge attack performance.

The purpose of this study was to investigate the differences in attack time and lower limb biomechanics when performing fencing lunge with fencing shoes (FS) and commonly used court shoes (CS). Additionally, the study aimed to evaluate whether fencing shoes with a heel cup (FSH) could reduce lower limb impact. Thirteen female collegiate fencers who had participated in national-level competitions were recruited for this study. Participants performed the lunge on a human-shaped target while wearing FS, FSH, or CS in a randomized order. Biomechanical data were collected using a 3D motion analysis system synchronized with a force plate. A signal light, and an accelerometer were attached to the target's head to initiate lunge movement and detect hit moment for calculating attack time. Attack time was significantly shorter when wearing FS (0.92 ± 0.05 s) and FSH (0.93 ± 0.07 s) compared to CS (0.96 ± 0.06 s). The maximum angular velocity of ankle plantarflexion in rear foot push-off phase was significantly slower when wearing FS and FSH than when wearing CS. The maximum knee posterior shear force, maximum knee flexion moment, and maximum ankle medial shear force during the front foot step phase were significantly greater when wearing FS than when wearing CS. These forces were significantly reduced or nearly significantly reduced when wearing FSH, and there were no significant differences compared to wearing CS. The maximum ankle medial shear force during the push-off phase in rear foot was the greatest when wearing FS but decreased significantly when using FSH. However, this force was still greater than when wearing CS. Wearing FS resulted in a higher loading rate (LR) on the front foot. This LR was reduced when a heel cup was used but still remained higher than when wearing CS. There were no significant differences in the forward extension of body, maximum ground reaction force, or center of pressure displacement during front foot step and rear foot push-off phases among the three shoe conditions. Wearing FS can enhance lunge performance, and the use of a heel cup can effectively reduce lower limb impact.

The effects of different iron shaft weights on golf swing performance.

This study examined the effects of three 7-iron shaft weights on golf swing performance among golfers of varying skill levels. The study included 10 low-handicap (LH; 4.3 ± 2.4) and 10 high-handicap (HH; 29.1 ± 5.4) right-handed golfers as participants. The participants were randomly assigned 7-iron clubs with shaft weights categorized as light (77 g), medium (98 g), or heavy (114 g), and they performed test shots. Kinematic data were captured using a motion analysis system with nine infra-red high speed cameras; a force platform connected to this system was used to record weight transfer patterns. Performance variables were assessed using a FlightScope launch monitor. A two-way mixed-design analysis of variance was used to determine the significance of the performance differences among both participant groups and golf shaft weights. The results indicated that during the backswing, the LH group exhibited significantly greater maximum rightward upper torso rotation, maximum X-factor, and maximum right wrist hinge rotation than did the HH group. During the downswing, the LH group exhibited significantly greater maximum upper torso angular velocity and maximum right wrist angular velocity than did the HH group. Moreover, the LH group produced significantly higher ball speeds, longer shot distances, and lower launch angles than did the HH group. The shaft weight neither greatly altered the golf swing nor displaced the center of gravity of the golfers. The lighter shafts were observed to facilitate faster clubhead speeds and initial ball velocities, thereby resulting in longer shot distances, especially among LH golfers. Although significant differences in swing mechanics and performance exist between HH and LH golfers, lighter shafts can contribute to increased shot distances for all golfers.

Pitching Biomechanics and Shoulder Function in Baseball Pitchers with Scapular Dyskinesis.

The primary purpose was to investigate the influence of scapular dyskinesis (SD) on pitching biomechanics and shoulder function in high school baseball pitchers. The secondary purpose was to identify possible factors associated with shoulder function in pitchers with SD. Thirty-eight pitchers were classified into the SD group (n=26) or the non-SD group (n=12). They were evaluated with the Kerlan-Jobe Orthopaedic Clinic shoulder and elbow (KJOC) scale and clinical measurements of shoulder characteristics, and with measurements of scapular kinematics, muscle activation, and ball speed during fastball pitching. Compared to the controls, the pitchers with SD had less scapular external rotation (difference=11.3 degrees, ES=0.92, p=0.012) during overall pitching and less upper trapezius (UT) activation during the late cocking (difference=7.1%, ES=0.79, p=0.019) and acceleration phases (difference=12.5%, ES=0.75, p=0.035). Higher UT activation during the late cocking phase was significantly associated with higher KJOC scores (standardized ß=0.415, p=0.039). In conclusion, deficits in scapular external rotation and decreased UT activation during pitching were found in pitchers with SD. Higher UT activation may be important for shoulder function in pitchers with SD.

A Comparison of Plyometric and Jump Rope Training Programs for Improving Punching Performance in Junior Amateur Boxers.

Improving lower extremity sports performance may contribute to punching performance in boxers. We compared the effects of two typical boxing routines for developing lower extremity sports performance and subsequent punching performance. Twenty-four high school amateur boxers between the ages of 12 and 18 performed training at least 3 days per week. All Athletes had 3-5 years of experience in boxing training. The participants separated into two groups to receive an 8-week plyometric or jump rope training program. They performed each training program for 30 min on 3 days/week. Lower extremity sports performance in countermovement jump (leg stiffness, jump power, and rate of force development) and jab-cross punching performance (punch velocity, punch force, reaction time, movement time, and ground reaction force) were assessed at pre-and post-training. The data were analyzed using a two-way mixed-design analysis of variance (ANOVA) (group × time). Both training programs improved the rate of force development in countermovement jump, the reaction time of punch, the peak ground reaction force of the rear leg during the jab punch, and the velocity of the jab punch. There were no group differences and interaction effects in all variables analyzed. It is concluded that 8 weeks of plyometric and rope jumping programs had a similar impact on improving lower extremity strength and punching performance. Both training programs may improve muscle strength and power, rate of force development, and reaction time. These improvements may contribute to lower extremity strength for driving a punch at the target with excellent performance.

Glenohumeral Internal Rotation Deficit on Pitching Biomechanics and Muscle Activity.

To characterize the scapular pitching biomechanics in symptomatic GIRD pitchers (SG) compared to asymptomatic GIRD (ASG) and healthy pitchers. The scapular kinematics and associated muscle activities during pitching were recorded in 33 high school pitchers. Compared to healthy, GIRD pitchers had less scapular posterior tilt in each pitching event (average difference, AD=14.4°, p<0.01) and ASG demonstrated less scapular upward rotation at ball release (AD=12.8°, p<0.01) and greater muscle activity in the triceps brachii in the early-cocking phase (AD=9.9%, p=0.015) and in the serratus anterior in the late-cocking phase (AD=30.8%, p<0.01). Additionally, SG had less muscular activity on triceps brachii in the acceleration phase and serratus anterior in the cocking phase (AD=37.8%, p=0.016; AD=15.5%, p<0.01, respectively) compared to ASG. GIRD pitchers exhibited less scapular posterior tilt during pitching, which may cause impingement. Since tightness of the anterior shoulder is a common cause of inadequacy of posterior tilt during arm elevation, stretching exercise of the anterior shoulder is recommended. Given the inadequate recruitment during pitching in the GIRD pitchers, symptoms may develop following potential impingement.

Dance intervention effects on physical function in healthy older adults: a systematic review and meta-analysis.

BACKGROUND AND OBJECTIVE: Dancing is a form of physical exercise associated with health benefits in older adults. Regular dancing can prolong healthy aging, maintain or even improve physical function, and thus enhance their quality of life. The aim of this review was to evaluate the effects of dance intervention on physical function performance in healthy older adults in randomized-controlled trials (RCTs). METHODS: Five electronic databases (Cochrane Library, PsycINFO, PubMed, Scopus, and Web of Science) were searched systematically until the end of June 2018 by two independent reviewers. These searches were limited to the English language and persons with average age older than 65. The tool from the Cochrane Collaboration was used to assess the risk of bias. A standard meta-analysis was performed using Review Manager Software version 5.3. RESULTS: Thirteen RCTs from a total of 1029 older participants were included in this meta-analysis. The results showed that dance intervention significantly improved mobility function and endurance performance when compared with control groups for healthy older adults. However, gait was not significantly improved through dancing. Studies included in this review were not enough to perform meta-analysis for the effectiveness of dance on balance and general health in healthy older adults. CONCLUSION: Overall, dance intervention was effective to improve physical function performance in healthy older adults. The results from this meta-analysis strengthen the evidence from previous individual studies. Properly organized dance intervention would be a safe and effective exercise to incorporate into daily life.

The immediate effects of a shoulder brace on muscle activity and scapular kinematics in subjects with shoulder impingement syndrome and rounded shoulder posture: A randomized crossover design.

BACKGROUND: Round shoulder posture (RSP) is one of the potential risks for shoulder impingement syndrome (SIS) due to alignment deviation of the scapula. Evidence on how the characteristics of a shoulder brace affecting the degree of RSP, shoulder kinematics, and associated muscle activity during movements is limited. RESEARCH QUESTION: The purposes of this study were (1) to compare the effects of a shoulder brace on clinical RSP measurements, muscle activities and scapular kinematics during arm movements in subjects with shoulder impingement syndrome (SIS) and RSP; and (2) to compare the effects of two configurations (parallel and diagonal) and two tensions (comfortable and forced tension) of the brace straps on muscle activities and scapular kinematics during arm movements in subjects with SIS and RSP. METHODS: Twenty-four participants (12 males; 12 females) with SIS and RSP were randomly assigned into 2 groups (comfortable then forced, and forced then comfortable) with 2 strap configurations in each tension condition. The pectoralis minor index (PMI), acromial distance (AD) and shoulder angle (SA) were used to assess the degree of RSP. Three-dimensional electromagnetic motion analysis and electromyography were used to record the scapular kinematics and muscle activity during arm movements. RESULTS: All clinical measurements with the brace were significantly improved (p < 0.05). Under forced tension, muscle activities were higher with the diagonal configuration than with the parallel configuration in the lower trapezius (LT) (1.2-2.3% MVIC, p < 0.05) and serratus anterior (SA) (2.3% MVIC, p = 0.015). For upward rotation and posterior tilting of the scapula, the diagonal configuration was larger than the parallel configuration (1.5°, p = 0.038; 0.4°-0.5°, p < 0.05, respectively). SIGNIFICANCE: Different characteristics of the straps of the shoulder brace could alter muscle activity and scapular kinematics at different angles during arm movement. Based on the clinical treatment preference, the application of a shoulder brace with a diagonal configuration and forced tension is suggested for SIS and RSP subjects.

Progressive conscious control of scapular orientation with video feedback has improvement in muscle balance ratio in patients with scapular dyskinesis: a randomized controlled trial.

BACKGROUND: Video feedback (VF) can guide patients to consciously control scapular orientation without inappropriate substitution. This study investigated whether progressive conscious control with VF improves scapular muscle activation and movements during arm elevation in patients with subacromial impingement and scapular dyskinesis. METHODS: The study recruited 38 amateur overhead athletes with subacromial impingement and scapular medial border prominence who were randomly assigned to the VF or control group. The participants in both groups controlled the scapular position and progressively practiced from 0° to 45° and from 0° to 90° of arm elevation. Participants in the VF group also controlled the scapular position with a video presentation of the scapula on a screen. We investigated the scapular kinematics, muscle activation, and balance ratio for outcome collection in the preintervention and postintervention conditions with and without VF conditions. RESULTS: Decreased upper trapezius (UT) activation (3%-13%, P < .0083), increased lower trapezius (LT) activation (3%-17%, P < .0083), restored UT/LT ratios (0.67-3.13, P < .0083), and decreased scapular internal rotation (1.8°-6.1°, P < .003) relative to the preintervention condition were demonstrated in the 2 postintervention conditions in both groups. The VF group also demonstrated decreased UT/serratus anterior ratios (0.21-0.30, P < .0083) in 2 postintervention conditions relative to the preintervention condition. CONCLUSIONS: The progressive control of scapular orientation with or without VF can be used to reduce the UT/LT ratio and improve scapular internal rotation during arm elevation. Control training with VF can further decrease the UT/serratus anterior ratio.

Hot Water Bathing Impairs Training Adaptation in Elite Teen Archers.

Despite heat imposes considerable physiological stress to human body, hot water immersion remains as a popular relaxation modality for athletes. Here we examined the lingering effect of hot tub relaxation after training on performance-associated measures and dehydroepiandrosterone sulfate (DHEA-S) in junior archers. Ten national level archers, aged 16.6 ± 0.3 years (M = 8, F = 2), participated in a randomized counter-balanced crossover study after baseline measurements. In particular, half participants were assigned to the hot water immersion (HOT) group, whereas another halves were assigned to the untreated control (CON) group. Crossover trial was conducted following a 2-week washout period. During the HOT trial, participants immersed in hot water for 30 min at 40°C, 1 h after training, twice a week (every 3 days) for 2 weeks. Participants during CON trial sat at the same environment without hot water after training. Performance-associated measures and salivary DHEA-S were determined 3 days after the last HOT session. We found that the HOT intervention significantly decreased shooting performance (CON: -4%; HOT: -22%, P < 0.05), postural stability (CON: +15%; HOT: -16%, P < 0.05), and DHEA-S levels (CON: -3%; HOT: -60%, P < 0.05) of archers, compared with untreated CON trial. No group differences were found in motor unit recruitment (root mean square electromyography, RMS EMG) of arm muscles during aiming, autonomic nervous activity (sympathetic and vagal powers of heart rate variability, HRV), and plasma cortisol levels after treatments. Our data suggest that physiological adaptation against heat exposure takes away the sources needed for normal training adaptation specific to shooting performance in archers.

Does ovulation affect performance in tennis players?

BACKGROUND: Scientific data on the performance of collegiate female tennis players during the menstrual phases are scarce. TRIAL DESIGN: Double-blind, counter-balanced, crossover trials were conducted to examine whether tennis performance was affected during menstruation, with and without dehydroepiandrosterone sulfate (DHEA-S) supplementation. METHODS: Ten Division 1 collegiate tennis players (aged 18-22 years) were evenly assigned into placebo-supplemented and DHEA-supplemented (25 mg/day) trials. Treatments were exchanged among the participants after a 28-day washout. Tennis serve performance was assessed on the first day of menstrual bleeding (day 0/28) and on days 7, 14 and 21. RESULTS: Mood state was unaltered during the menstrual cycles in both trials. The lowest tennis serve performance score (speed times accuracy) occurred on day 14 (P=0.06 vs day 0; P=0.01 vs day 21) in both placebo and DHEA trials. Decreased performance on day 14 was explained by decreased accuracy (P=0.03 vs day 0/28; P=0.01 vs day 21), but not velocity itself. Isometric hip strength, but not quadriceps strength, was moderately lower on day 14 (P=0.08). Increasing plasma DHEA-S (by ~65%) during the DHEA-supplemented trial had no effects on mood state, sleep quality or tennis serve performance. CONCLUSION: We have shown that menses does not affect serve performance of collegiate tennis players. However, the observed decrement in the accuracy of serve speed near ovulation warrants further investigation.

Deep Ocean Mineral Supplementation Enhances the Cerebral Hemodynamic Response during Exercise and Decreases Inflammation Postexercise in Men at Two Age Levels.

Background: Previous studies have consistently shown that oral supplementation of deep ocean minerals (DOM) improves vascular function in animals and enhances muscle power output in exercising humans. Purpose: To examine the effects of DOM supplementation on the cerebral hemodynamic response during physical exertion in young and middle-aged men. Design: Double-blind placebo-controlled crossover studies were conducted in young (N = 12, aged 21.2 ± 0.4 years) and middle-aged men (N = 9, aged 46.8 ± 1.4 years). The counter-balanced trials of DOM and Placebo were separated by a 2-week washout period. DOM and Placebo were orally supplemented in drinks before, during, and after cycling exercise. DOM comprises desalinated minerals and trace elements from seawater collected ~618 m below the earth's surface. Methods: Cerebral hemodynamic response (tissue hemoglobin) was measured during cycling at 75% VO2max using near infrared spectroscopy (NIRS). Results: Cycling time to exhaustion at 75% VO2max and the associated plasma lactate response were similar between the Placebo and DOM trials for both age groups. In contrast, DOM significantly elevated cerebral hemoglobin levels in young men and, to a greater extent, in middle-aged men compared with Placebo. An increased neutrophil to lymphocyte ratio (NLR) was observed in middle-aged men, 2 h after exhaustive cycling, but was attenuated by DOM. Conclusion: Our data suggest that minerals and trace elements from deep oceans possess great promise in developing supplements to increase the cerebral hemodynamic response against a physical challenge and during post-exercise recovery for middle-aged men.

Effects of an eight-week whole body vibration on lower extremity muscle tone and function in children with cerebral palsy.

The aim of this study was to evaluate the effect of an eight-week whole body vibration (WBV) on lower extremity spasticity and ambulatory function in children with cerebral palsy with a complete crossover design. Sixteen participants aged 9.2 (2.1) years participated in this study. Half of the participants received a 10-min WBV, 3 times a week for 8 weeks. Then a 4-week washout period followed, after which they received a sham WBV 3 times a week for 8 weeks. The other half received the intervention in a reversed order. The participants were evaluated via variables measuring range-of-motion, muscle tone, and ambulatory function before, immediately after, 1 day after, and 3 days after each intervention. Repeated-measures analyses revealed significant beneficial effects on most variables expect the passive range-of-motion measurement. Significant correlations were found between timed up-and-go and relaxation index, and between timed up-and-go and six-minute walk test. The results suggested that an 8-week WBV intervention normalized muscle tone, improved active joint range and enhanced ambulatory performance in children with cerebral palsy for at least 3 days. These indicated that regular WBV can serve as an alternative, safe, and efficient treatment for these children in both clinical and home settings.

Comprehensive classification test of scapular dyskinesis: A reliability study.

BACKGROUND: Assessment of scapular dyskinesis (SD) is of clinical interest, as SD is believed to be related to shoulder pathology. However, no clinical assessment with sufficient reliability to identify SD and provide treatment strategies is available. OBJECTIVES: The purpose of this study was to investigate the reliability of the comprehensive SD classification method. DESIGN: Cross-sectional reliability study. METHOD: Sixty subjects with unilateral shoulder pain were evaluated by two independent physiotherapists with a visual-based palpation method. SD was classified as single abnormal scapular pattern [inferior angle (pattern I), medial border (pattern II), superior border of scapula prominence or abnormal scapulohumeral rhythm (pattern III)], a mixture of the above abnormal scapular patterns, or normal pattern (pattern IV). The assessment of SD was evaluated as subjects performed bilateral arm raising/lowering movements with a weighted load in the scapular plane. Percentage of agreement and kappa coefficients were calculated to determine reliability. RESULTS: Agreement between the 2 independent physiotherapists was 83% (50/60, 6 subjects as pattern III and 44 subjects as pattern IV) in the raising phase and 68% (41/60, 5 subjects as pattern I, 12 subjects as pattern II, 12 subjects as pattern IV, 12 subjects as mixed patterns I and II) in the lowering phase. The kappa coefficients were 0.49-0.64. CONCLUSIONS: We concluded that the visual-based palpation classification method for SD had moderate to substantial inter-rater reliability. The appearance of different types of SD was more pronounced in the lowering phase than in the raising phase of arm movements.

Seat surface inclination may affect postural stability during Boccia ball throwing in children with cerebral palsy.

The aim of the study was to examine how seat surface inclination affects Boccia ball throwing movement and postural stability among children with cerebral palsy (CP). Twelve children with bilateral spastic CP (3 with gross motor function classification system Level I, 5 with Level II, and 4 with Level III) participated in this study. All participants underwent pediatric reach tests and ball throwing performance analyses while seated on 15° anterior- or posterior-inclined, and horizontal surfaces. An electromagnetic motion analysis system was synchronized with a force plate to assess throwing motion and postural stability. The results of the pediatric reach test (p = 0.026), the amplitude of elbow movement (p = 0.036), peak vertical ground reaction force (PVGRF) (p < 0.001), and movement range of the center of pressure (COP) (p < 0.020) were significantly affected by seat inclination during throwing. Post hoc comparisons showed that anterior inclination allowed greater amplitude of elbow movement and PVGRF, and less COP movement range compared with the other inclines. Posterior inclination yielded less reaching distance and PVGRF, and greater COP movement range compared with the other inclines. The anterior-inclined seat yielded superior postural stability for throwing Boccia balls among children with bilateral spastic CP, whereas the posterior-inclined seat caused difficulty.

Motion analysis of throwing Boccia balls in children with cerebral palsy.

Boccia is a sport suitable for children with cerebral palsy (CP). Throwing Boccia balls requires upper extremity and torso coordination. This study investigated the differences between children with CP and normally developed children regarding throwing patterns of Boccia balls. Thirteen children with bilateral spastic CP and 20 normally developed children participated in this study. The tests in this study were a pediatric reach test and throwing of Boccia balls. A 3D electromagnetic motion tracking system and a force plate were synchronized to record and analyze biomechanical parameters of throwing Boccia balls. The results of the pediatric reach test for participants with CP were significantly worse than those for normally developed participants. The 2 groups of participants did not significantly differ regarding the distance between a thrown Boccia ball and a target ball (jack). Participants with CP demonstrated significantly longer movement duration, smaller amplitude of elbow movement, greater amplitudes of shoulder abduction and flexion, slower maximal velocity of torso flexion and the linear velocity of moving the wrist joint forward, faster maximal velocity of head flexion, and smaller sway ratio compared with normally developed participants when throwing Boccia balls. Participants with CP seemed to mainly use head and shoulder movements to bring the Boccia balls forward with limited torso movement. Normally developed participants brought the Boccia ball forward with faster torso and greater elbow movement while stabilizing head and shoulder movements. Nevertheless, participants with CP did not demonstrate significantly worse performance in the throwing accuracy of Boccia balls.

Deep ocean mineral water accelerates recovery from physical fatigue.

BACKGROUND: Deep oceans have been suggested as a possible site where the origin of life occurred. Along with this theoretical lineage, experiments using components from deep ocean water to recreate life is underway. Here, we propose that if terrestrial organisms indeed evolved from deep oceans, supply of deep ocean mineral water (DOM) to humans, as a land creature, may replenish loss of molecular complexity associated with evolutionary sea-to-land migration. METHODS: We conducted a randomized, double-blind, placebo-controlled crossover human study to evaluate the effect of DOM, taken from a depth of 662 meters off the coast of Hualien, Taiwan, on time of recovery from a fatiguing exercise conducted at 30°C. RESULTS: The fatiguing exercise protocol caused a protracted reduction in aerobic power (reduced VO2max) for 48 h. However, DOM supplementation resulted in complete recovery of aerobic power within 4 h (P < 0.05). Muscle power was also elevated above placebo levels within 24 h of recovery (P < 0.05). Increased circulating creatine kinase (CK) and myoglobin, indicatives of exercise-induced muscle damage, were completely eliminated by DOM (P < 0.05) in parallel with attenuated oxidative damage (P < 0.05). CONCLUSION: Our results provide compelling evidence that DOM contains soluble elements, which can increase human recovery following an exhaustive physical challenge.

Topical cooling (icing) delays recovery from eccentric exercise-induced muscle damage.

It is generally thought that topical cooling can interfere with blood perfusion and may have positive effects on recovery from a traumatic challenge. This study examined the influence of topical cooling on muscle damage markers and hemodynamic changes during recovery from eccentric exercise. Eleven male subjects (age 20.2 ± 0.3 years) performed 6 sets of elbow extension at 85% maximum voluntary load and randomly assigned to topical cooling or sham groups during recovery in a randomized crossover fashion. Cold packs were applied to exercised muscle for 15 minutes at 0, 3, 24, 48, and 72 hours after exercise. The exercise significantly elevated circulating creatine kinase-MB isoform (CK-MB) and myoglobin levels. Unexpectedly, greater elevations in circulating CK-MB and myoglobin above the control level were noted in the cooling trial during 48-72 hours of the post-exercise recovery period. Subjective fatigue feeling was greater at 72 hours after topical cooling compared with controls. Removal of the cold pack also led to a protracted rebound in muscle hemoglobin concentration compared with controls. Measures of interleukin (IL)-8, IL-10, IL-1ß, and muscle strength during recovery were not influenced by cooling. A peak shift in IL-12p70 was noted during recovery with topical cooling. These data suggest that topical cooling, a commonly used clinical intervention, seems to not improve but rather delay recovery from eccentric exercise-induced muscle damage.

A comparison of physical characteristics and swing mechanics between golfers with and without a history of low back pain.

STUDY DESIGN: Controlled laboratory study using a cross-sectional design. OBJECTIVES: To examine the kinematics and kinetics of the trunk and the physical characteristics of trunk and hip in golfers with and without a history of low back pain (LBP). BACKGROUND: Modified swing patterns and general exercises have been suggested for golfers with back pain. Yet we do not know what contributes to LBP in golfers. To create and validate a low back-specific exercise program to help prevent and improve back injuries in golfers, it may be valuable to understand the differences in biomechanical and physical characteristics of golfers with and without a history of LBP. METHODS: Sixteen male golfers with a history of LBP were matched by age and handicap with 16 male golfers without a history of LBP. All golfers underwent a biomechanical swing analysis, trunk and hip strength and flexibility assessment, spinal proprioception testing, and postural stability testing. RESULTS: The group with a history of LBP demonstrated significantly less trunk extension strength at 60 degrees/s and left hip adduction strength, as well as limited trunk rotation angle toward the nonlead side. No significant differences were found in postural stability, trunk kinematics, and maximum spinal moments during the golf swing. CONCLUSION: Deficits observed in this study may affect a golfer's ability to overcome the spinal loads generated during the golf swing over time. Exercises for improving these physical deficits can be considered, although the cause-effect of LBP in golfers still cannot be determined.

A comparison of throwing kinematics between youth baseball players with and without a history of medial elbow pain.

Risk factors in throwing factors associated to little league elbow have not been adequately explored. Whether these factors also affect the players' performance is also important to elucidate while modifying throwing pattern to reduce injury. The purpose of this study was to compare the differences in throwing kinematics between youth baseball players with or without a history of medial elbow pain (MEP) and to determine the relationship between their throwing kinematics and ball speed. Fifteen players with previous MEP were matched with 15 healthy players by age, height and weight. Throwing kinematics was recorded by an electromagnetic motion analysis system. A foot switch was used for determining foot off and foot contact. Ball speed was recorded with a sports radar gun. The group with a history of MEP demonstrated less elbow flexion angle at maximum shoulder external rotation and had more lateral trunk tilt at ball release compared to the healthy group. The group with a history of MEP also had faster maximum upper torso rotation velocities, maximum pelvis rotation velocities and ball speeds. Maximum shoulder external rotation angle (r = 0.458, P = 0.011), elbow flexion angle at maximum shoulder external rotation (r = -0.637, P = 0.0003), and maximum upper torso rotation velocity (r = 0.562, P = 0.002) had significant correlation with ball speed. Findings of this study can be treated as elbow injury-related factors that clinicians and coaches can attend to when taking care of youth

The role of upper torso and pelvis rotation in driving performance during the golf swing.

While the role of the upper torso and pelvis in driving performance is anecdotally appreciated by golf instructors, their actual biomechanical role is unclear. The aims of this study were to describe upper torso and pelvis rotation and velocity during the golf swing and determine their role in ball velocity. One hundred recreational golfers underwent a biomechanical golf swing analysis using their own driver. Upper torso and pelvic rotation and velocity, and torso-pelvic separation and velocity, were measured for each swing. Ball velocity was assessed with a golf launch monitor. Group differences (groups based on ball velocity) and moderate relationships (r > or = 0.50; P < 0.001) were observed between an increase in ball velocity and the following variables: increased torso-pelvic separation at the top of the swing, maximum torso-pelvic separation, maximum upper torso rotation velocity, upper torso rotational velocity at lead arm parallel and last 40 ms before impact, maximum torso-pelvic separation velocity and torso-pelvic separation velocity at both lead arm parallel and at the last 40 ms before impact. Torso-pelvic separation contributes to greater upper torso rotation velocity and torso-pelvic separation velocity during the downswing, ultimately contributing to greater ball velocity. Golf instructors can consider increasing ball velocity by maximizing separation between the upper torso and pelvis at the top of and initiation of the downswing.