Sport-specific Movements Research Articles

Current Perspectives on Profiling and Enhancing Wheelchair Court Sport Performance.

Despite the growing interest in Paralympic sport, the evidence base for supporting elite wheelchair sport performance remains in its infancy when compared with able-bodied (AB) sport. Subsequently, current practice is often based on theory adapted from AB guidelines, with a heavy reliance on anecdotal evidence and practitioner experience. Many principles in training prescription and performance monitoring with wheelchair athletes are directly transferable from AB practice, including the periodization and tapering of athlete loads around competition, yet considerations for the physiological consequences of an athlete's impairment and the interface between athlete and equipment are vital when targeting interventions to optimize in-competition performance. Researchers and practitioners are faced with the challenge of identifying and implementing reliable protocols that detect small but meaningful changes in impairment-specific physical capacities and on-court performance. Technologies to profile both linear and rotational on-court performance are an essential component of sport-science support to understand sport-specific movement profiles and prescribe training intensities. In addition, an individualized approach to the prescription of athlete training and optimization of the "wheelchair-user interface" is required, accounting for an athlete's anthropometrics, sports classification, and positional role on court. In addition to enhancing physical capacities, interventions must focus on the integration of the athlete and his or her equipment, as well as techniques for limiting environmental influence on performance. Taken together, the optimization of wheelchair sport performance requires a multidisciplinary approach based on the individual requirements of each athlete.

Central neuronal motor behaviour in skilled and less skilled novices – Approaching sports-specific movement techniques

Research on motor behavioural processes preceding voluntary movements often refers to analysing the readiness potential (RP). For this, decades of studies used laboratory setups with controlled sports-related actions. Further, recent applied approaches focus on athlete-non-athlete comparisons, omitting possible effects of training history on RP. However, RP preceding real sport-specific movements in accordance to skill acquisition remains to be elucidated.Therefore, after familiarization 16 right-handed males with no experience in archery volunteered to perform repeated sports-specific movements, i.e. 40 arrow-releasing shots at 60s rest on a 15m distant standard target. Continuous, synchronised EEG and right limb EMG recordings during arrow-releasing served to detect movement onsets for RP analyses over distinct cortical motor areas. Based on attained scores on target, archery novices were, a posteriori, subdivided into a skilled and less skilled group. EMG results for mean values revealed no significant changes (all p>0.05), whereas RP amplitudes and onsets differed between groups but not between motor areas. Arrow-releasing preceded larger RP amplitudes (p<0.05) and later RP onsets (p<0.05) in skilled compared to less skilled novices. We suggest this to reflect attentional orienting and greater effort that accompanies central neuronal preparatory states of a sports-specific movement.

The validity and reliability of a 5-hz GPS device for quantifying athletes’ sprints and movement demands specific to team sports

GPS systems are commonly used to analysis football performance during either trainings or matches. While many studies have investigated the validity and reliability of these devices, there is a lack of objective procedures regarding synchronization with gold standards such as real distance or timing gates. The objective of this study was to study the validity and reliability of a 5Hz GPS system (WIMU) during 10m and 30m sprints and during team sports specific movements and the reliability during very high speeds (> 30 km/h). The TD BIAS for Circuit A, 10m sprint and 30m sprint were -2.73 ± 1.64 m (p < 0.001), -0.80 ± 0.58 m (p<0.001) and 0.42 ± 2.50 m (p=0.515) respectively. Average ICC for GPS speed point-to-point were 0.976 ± 0.012 and 0.991± 0.003 for Circuit B and Motorized Sprints, respectively. The average BIAS compared with each unit mean laps (intra-unit reliability) results for TD, Peak-Speed and Avg-Speed were 0.00 ± 1.68, 0.00 ± 1.73 and 0.00 ± 0.33 for Circuit A, 0.00 ± 0.49, 0.00 ± 0.53 and 0.00 ± 0.77 for 10m sprints and 0.00 ± 2.34, 0.00 ± 0.76 and 0.00 ± 0.74 for 30m sprints, non-significant difference in all cases. In conclusion, despite a lower than recommended sample frequency, the WIMU GPS showed to be valid and reliable for measuring sprints at speed higher than 20 km· h -1 , as well as for team sport movements. This might be practical on daily physical demands testing during training sessions

Effects of plyometric exercise training with external weights on punching ability of experienced amateur boxers.

During competition, a boxer must continue to deliver high-impact punches despite increasing fatigue. It is unclear whether the effects of plyometric training using external weights are transferred to sport-specific movements such as punching. The aim of the study was to investigate the effects of a 4-week cycle of plyometric training with external weights on punching ability. The study involved eight male amateur boxers aged 22.3±2.5 years with at least 7 years of competitive experience. They performed 12 plyometric training sessions, each comprising eight exercises of various muscle groups performed at maximum movement velocity. Six drills were performed with external weights, and two drills were performed using the body weight as resistance. All exercises required coordination. The punching ability was tested at baseline and after the 4 weeks of training using the Kiktest-100 boxing bag. The force of single punches and the frequency of punches within a series did not change from before to after the 4 weeks, except for increased power in the rear-hand low punch (P<0.05). However, there was an increase in summative force and energy output within 3 s and 8 s, and in a series of eight 8-s tests (P<0.05). Four weeks of plyometric training with external weights did not change the maximum punching power or movement frequency significantly, but had a beneficial effect on punching power endurance in boxers.

A Kinematic Analysis of Fundamental Movement Skills

Abstract Fundamental movement skills are considered the basic building blocks for movement and provide the foundation for specialized and sport-specific movement skills required for participation in a variety of physical activities. However, kinematic analyses of fundamental movement has not been performed. The aims of this study were to, (1) characterise the relationship between facets of fundamental movement and, (2) characterise the relationship between overall integrated acceleration and three-dimensional kinematic variables whilst performing fundamental movement skills. Eleven participants (10±0.8y, 1.41±0.07m, 33.4±8.6kg, body mass index; 16.4±3.1 kg·m2) took part in this study, had anthropometric variables recorded and performed a series of fundamental movement tasks, whilst wearing a tri-axial accelerometer and were recorded using a three-dimensional motion capture system. Maximum shoulder external rotation (°) and maximum shoulder internal rotation velocity (°.s−1) (r=0.86, p&lt;0.001), mediolateral centre of mass range (cm) and centre of mass coefficient of variation (%) (r=0.83, p&lt;0.001), maximum stride angle (°) in the jog and walk (r=0.74, p=0.01) and maximum sprint stride angle and maximum shoulder internal rotation velocity (°.s−1) (r=0.67, p&lt;0.02) were significantly correlated. Maximum sprint stride angle (hip: r=0.96, p&lt;0.001, ankle: r=0.97, p&lt;0.001) and maximum internal rotation velocity (ankle: r=0.6, p=0.05) were significantly correlated to overall integrated acceleration. Overall integrated acceleration was comparable between participants (CV: 10.5), whereas three-dimensional variables varied by up to 65%. Although overall integrated acceleration was comparable between participants, three-dimensional variables were much more varied. Indicating that although overall activity may be correspondent, the characteristics of a child’s movement may be highly varied.

Differences in Muscle Activity During Cable Resistance Training Are Influenced by Variations in Handle Types.

Rendos, NK, Heredia Vargas, HM, Alipio, TC, Regis, RC, Romero, MA, and Signorile, JF. Differences in muscle activity during cable resistance training are influenced by variations in handle types. J Strength Cond Res 30(7): 2001-2009, 2016-There has been a recent resurgence in the use of cable machines for resistance training allowing movements that more effectively simulate daily activities and sports-specific movements. By necessity, these devices require a machine/human interface through some type of handle. Considerable data from material handling, industrial engineering, and exercise training studies indicate that handle qualities, especially size and shape, can significantly influence force production and muscular activity, particularly of the forearm muscles, which affect the critical link in activities that require object manipulation. The purpose for this study was to examine the influence of three different handle conditions: standard handle (StandH), ball handle with the cable between the index and middle fingers (BallIM), and ball handle with the cable between the middle and ring fingers (BallMR), on activity levels (rmsEMG) of the triceps brachii lateral and long heads (TriHLat, TriHLong), brachioradialis (BR), flexor carpi radialis (FCR), extensor carpi ulnaris, and extensor digitorum (ED) during eight repetitions of standing triceps pushdown performed from 90° to 0° elbow flexion at 1.5 s per contractile stage. Handle order was randomized. No significant differences were seen for triceps or BR rmsEMG across handle conditions; however, relative patterns of activation did vary for the forearm muscles by handle condition, with more coordinated activation levels for the FCR and ED during the ball handle conditions. In addition, the rmsEMG for the ED was significantly higher during the BallIM than any other condition and during the BallMR than the StandH. These results indicate that the use of ball handles with the cable passing between different fingers can vary the utilization patterns of selected forearm muscles and may therefore be advantageous for coaches, personal trainers, therapists, or bodybuilders for targeted training or rehabilitation of these muscles.

Comparison of Medial Knee Displacement Assessment on the Overhead Squat and Landing Error Scoring System

Medial knee displacement (MKD) in females has been associated with increased risk for anterior cruciate ligament injury (ACL). It can be reliably detected using clinical movement screens and is readily modifiable through corrective exercise. The Overhead Squat (OHS) and Landing Error Scoring System (LESS) are both valid indicators of MKD. PURPOSE:To determine concordance between evaluation of MKD from the OHS relative to the more dynamic LESS. METHODS: Female U.S. Military applicants (n=84, 20.6±2.7 yrs, 161.4±6.7 cm, 60.4±8.3 kg) from the Baltimore MEPS performed the OHS and LESS prior to entering military basic training. MKD for both tests was evaluated dichotomously: 0 indicating no MKD and 1 indicating the presence of MKD. The OHS was evaluated in real time. MKD on the LESS was evaluated at maximum knee flexion. McNemar’s Test for non-homogeneity was performed to determine paired proportions of MKD between the OHS and LESS. RESULTS: A total of 55 females (65.4%) displayed MKD on the OHS, and 76 females (90.5%) had MKD on the LESS. McNemar’s test showed non-homogeneity for MKD detection on both the OHS and LESS (Χ2= 15.21, p<0.001); the majority of females (60.7%, n=51) who displayed MKD on the OHS also displayed MKD on the LESS. However, 29.8% (n=25) of females who displayed MKD on the LESS did not display MKD on the OHS. Only 4 (4.8%) females did not display MKD on either screen. CONCLUSION: The OHS and LESS are both commonly used clinical screens for assessing MKD, a risk factor for ACL injury in females. Although the majority of females who displayed MKD on the OHS also displayed it on the LESS, 29.8% only displayed MKD on the more dynamic LESS suggesting that MKD manifests differently between static and dynamic tasks. Both screens have been biomechanically validated as indicators of MKD, but the dynamic task requirements of the LESS may be more representative of sport-specific movement. Further analyses comparing injury rates in recruits with MKD detected by OHS versus LESS are pending. The LESS could be a more accurate test for assessing dynamic MKD as a readily modifiable risk factor for ACL injury in females.

Sport-specific functional movement can simulate aspects of neuromuscular fatigue occurring in team sports

Fatigue protocols have been used over the years to examine muscular exhaustion. As an alternative to approaches in laboratory settings, functional agility protocols claiming to mimic the multifaceted loads of athletic activity have been proposed. This study aimed to examine the effects of a functional agility short-term fatigue protocol (FAST-FP) on neuromuscular function. Twenty-eight healthy sports students (15 males, aged 24.3 ± 2.4 years) completed the FAST-FP, which consists of four components: three counter-movement jumps (90% of individual maximum), a 20-s bout of step-ups, three bodyweight squats and an agility run. Tasks were repeated until the participants no longer achieved the required jump height in two consecutive sets. Outcomes (pre-post) encompassed subjective exhaustion (visual analogue scale [VAS]), maximum isometric voluntary force of the knee extensors (MIVF), reactive strength index (RSI), mean power frequency (MPF, measured using surface electromyography) and maximum knee range of motion (ROM). Post-intervention, VAS (+54 mm) increased significantly, while MIVF (–6.1%), RSI (–10.7%) and MPF (–4.1%) were reduced (p < 0.05). No changes were observed for ROM (p > 0.05). The FAST-FP induces small-to-moderate impairments in neuromuscular function and considerable self-perceived fatigue. Current evidence on exhaustion developing in team sports suggests that this magnitude of fatigue is similar. The protocol might thus be valuable in the evaluation of treatments counteracting post-match fatigue in team sports.

Influence of a Training Session on Postural Stability and Foot Loading Patterns in Soccer Players.

Sport specific movements coming along with characteristic plantar pressure distribution and a fatigue of muscles result in an increasing postural sway and therefore lead to a decrease in balance control. Although single soccer specific movements were expatiated with respect to these parameters, no information is available for a complete training session. The objective of the present observational study was to analyze the direct influence of soccer training on postural stability and gait patterns and whether or not these outcomes were altered by age. One hundred and eighteen experienced soccer players participated in the study and were divided into two groups. Group 1 contained 64 soccer players (age 13.31±0.66 years) and Group 2 contains 54 ones (age 16.74±0.73 years). Postural stability, static plantar pressure distribution and dynamic foot loading patterns were measured. Our results showed that the soccer training session, as well as the age, has relevant influence on postural stability, while the age only (excluding the training) has an influence on static plantar pressure distribution. The parameters of dynamic assessment seem therefore to be affected by age, training and a combination of both. Training and young age correlate with a decreased postural stability; they lead to a significant increase of peak pressure in the previously most loaded areas, and, after reaching a certain age and magnitude of absolute values, to a change in terminal stance and preswing phase of the roll-over. Moreover, younger players show an inhomogenous static plantar pressure distribution which might be the result of the decreased postural control in the young age.

Effects of Six Weeks of Medicine Ball Training on Throwing Velocity, Throwing Precision, and Isokinetic Strength of Shoulder Rotators in Female Handball Players.

The aim of this study was to investigate the effects of 6 weeks of medicine ball training (MBT) on throwing velocity, throwing precision, and isokinetic strength of shoulder rotators in competitive female handball players. Twenty-eight players (mean ± SD; age: 20.8 ± 3.3 years, height: 170.5 ± 5.6 cm, body mass: 65.2 ± 8.0 kg) were randomly assigned to an MBT group (TG; n = 15) and a control group (CG; n = 13). TG performed a supervised MBT program, 3 times a week for a total of 6 weeks, focusing on handball-specific movement patterns. Both groups, TG and CG, also conducted a supervised shoulder injury prevention program with elastic tubes, as part of the warm-up, finishing with regular handball throws. Results showed a significant group × time interaction in throwing velocity (p < 0.001) with the TG posttest results being significantly higher compared with CG (d = 2.1), and also a significant main time effect (p < 0.001), with an increase in throwing velocity of 14% (d = 3.0) and 3.7% (d = 0.3) for both TG and CG, respectively. Throwing precision did not significantly differ between groups and time points. Isokinetic strength measures revealed a significant group × time interaction (p ≤ 0.05) with the TG posttest results being significantly higher compared with CG (d = 0.9) and also a significant main time effect (p < 0.01) with an increase of 15% (d = 0.9) in concentric shoulder internal rotation at 180°·s⁻¹ in the dominant arm in TG, whereas no significant changes occurred in CG. The present results indicate that 6 weeks of MBT elicit significant improvements in functional performance (i.e., throwing velocity) in female handball players, whereas throwing precision remained unaffected. Medicine ball training exercises seem to be a useful and inexpensive strength training strategy in enhancing functional performance by closely mimicking sport-specific movement activities.

Biomechanical symmetry in elite rugby union players during dynamic tasks: an investigation using discrete and continuous data analysis techniques

BackgroundWhile measures of asymmetry may provide a means of identifying individuals predisposed to injury, normative asymmetry values for challenging sport specific movements in elite athletes are currently lacking in the literature. In addition, previous studies have typically investigated symmetry using discrete point analyses alone. This study examined biomechanical symmetry in elite rugby union players using both discrete point and continuous data analysis techniques.MethodsTwenty elite injury free international rugby union players (mean ± SD: age 20.4 ± 1.0 years; height 1.86 ± 0.08 m; mass 98.4 ± 9.9 kg) underwent biomechanical assessment. A single leg drop landing, a single leg hurdle hop, and a running cut were analysed. Peak joint angles and moments were examined in the discrete point analysis while analysis of characterising phases (ACP) techniques were used to examine the continuous data. Dominant side was compared to non-dominant side using dependent t-tests for normally distributed data or Wilcoxon signed-rank test for non-normally distributed data. The significance level was set at α = 0.05.ResultsThe majority of variables were found to be symmetrical with a total of 57/60 variables displaying symmetry in the discrete point analysis and 55/60 in the ACP. The five variables that were found to be asymmetrical were hip abductor moment in the drop landing (p = 0.02), pelvis lift/drop in the drop landing (p = 0.04) and hurdle hop (p = 0.02), ankle internal rotation moment in the cut (p = 0.04) and ankle dorsiflexion angle also in the cut (p = 0.01). The ACP identified two additional asymmetries not identified in the discrete point analysis.ConclusionsElite injury free rugby union players tended to exhibit bi-lateral symmetry across a range of biomechanical variables in a drop landing, hurdle hop and cut. This study provides useful normative values for inter-limb symmetry in these movement tests. When examining symmetry it is recommended to incorporate continuous data analysis techniques rather than a discrete point analysis alone; a discrete point analysis was unable to detect two of the five asymmetries identified.Electronic supplementary materialThe online version of this article (doi:10.1186/s13102-015-0006-9) contains supplementary material, which is available to authorized users.

Combined Arthroscopic Bankart Repair and Coracoid Process Transfer to Anterior Glenoid for Shoulder Dislocation in Rugby Players: Evaluation Based on Ability to Perform Sport-Specific Movements Effectively

To evaluate the outcomes of a combination of an arthroscopic Bankart repair and an open Bristow procedure in relation to the subjective quality of performance in movements that are typical in rugby. Forty shoulders in 38 players who underwent surgery for traumatic anterior instability of the shoulder were reviewed. In all cases, arthroscopic Bankart repair was followed by a Bristow procedure, with preservation of the repaired capsular ligaments, during the same operation. The mean age at the time of surgery was 21 years. Patients were asked to describe common rugby maneuvers (tackle, hand-off, jackal, and saving) preoperatively and postoperatively as "no problem," "insufficient," or "impossible." There were no recurrent dislocations at a mean follow-up of 30.5 months. The mean Rowe score improved significantly from 65.0 (range, 55 to 75) to 97.5 (range, 95 to 100) (P < .001) after surgery. Preoperatively, regarding the tackling motion, none of the patients reported having no problem, whereas the ability was described as insufficient for 23 shoulders and impossible for 17 shoulders. Postoperatively, no problem with tackling was reported for 36 shoulders, whereas insufficiency was reported for 4. The results for the hand-off, jackal, and saving maneuvers were similar (P < .001). No patient rated any of the motions as impossible postoperatively. This combined surgical procedure clearly is effective in preventing recurrent dislocation in rugby players; however, some players complained of insufficiency in the quality of their play when they were tackling or performing other rugby-specific movements. Level IV, case series.

The Use of Wearable Microsensors to Quantify Sport-Specific Movements.

Microtechnology has allowed sport scientists to understand the locomotor demands of various sports. While wearable global positioning technology has been used to quantify the locomotor demands of sporting activities, microsensors (i.e. accelerometers, gyroscopes and magnetometers) embedded within the units also have the capability to detect sport-specific movements. The objective of this study was to determine the extent to which microsensors (also referred to as inertial measurement units and microelectromechanical sensors) have been utilised in quantifying sport-specific movements. A systematic review of the use of microsensors and associated terms to evaluate sport-specific movements was conducted; permutations of the terms used included alternate names of the various technologies used, their applications and different applied environments. Studies for this review were published between 2008 and 2014 and were identified through a systematic search of six electronic databases: Academic Search Complete, CINAHL, PsycINFO, PubMed, SPORTDiscus, and Web of Science. Articles were required to have used athlete-mounted sensors to detect sport-specific movements (e.g. rugby union tackle) rather than sensors mounted to equipment and monitoring generic movement patterns. A total of 2395 studies were initially retrieved from the six databases and 737 results were removed as they were duplicates, review articles or conference abstracts. After screening titles and abstracts of the remaining papers, the full text of 47 papers was reviewed, resulting in the inclusion of 28 articles that met the set criteria around the application of microsensors for detecting sport-specific movements. Eight articles addressed the use of microsensors within individual sports, team sports provided seven results, water sports provided eight articles, and five articles addressed the use of microsensors in snow sports. All articles provided evidence of the ability of microsensors to detect sport-specific movements. Results demonstrated varying purposes for the use of microsensors, encompassing the detection of movement and movement frequency, the identification of movement errors and the assessment of forces during collisions. This systematic review has highlighted the use of microsensors to detect sport-specific movements across a wide range of individual and team sports. The ability of microsensors to capture sport-specific movements emphasises the capability of this technology to provide further detail on athlete demands and performance. However, there was mixed evidence on the ability of microsensors to quantify some movements (e.g. tackling within rugby union, rugby league and Australian rules football). Given these contrasting results, further research is required to validate the ability of wearable microsensors containing accelerometers, gyroscopes and magnetometers to detect tackles in collision sports, as well as other contact events such as the ruck, maul and scrum in rugby union.

Adaptation of local muscle blood flow and surface electromyography to repeated bouts of eccentric exercise.

The aim of this randomized controlled crossover study was to investigate the effect of a bout of unaccustomed eccentric exercise (ECC) followed by a consecutive bout of the same intensity on local muscle blood flow, amplitude, and frequency of the electromyographic (EMG) signal from the exercised tibialis anterior muscle. Sixteen healthy male participants (age, 25.7 (0.6) years; body mass index 24.8 (1) kg·m(-2) participated in this study. Two identical bouts of high-intensity ECC were performed on the tibialis anterior muscle 7 days apart. Control sessions involving no exercise were performed 4 weeks either before or after the exercise sessions. Changes in local total blood flow [ΔtHb], EMG root mean square, and median power frequency were recorded during isometric maximum voluntary contraction of ankle dorsiflexion. Measurements were performed before, immediately after, and the day after both ECCs (ECC1 and ECC2). The participants rested quietly in a chair in the control session. Eccentric exercise 1 led to a significant decrease in [ΔtHb] on the day after (p ≤ 0.05), whereas ECC2 did not. Median power frequency decreased significantly in ECC2 compared with ECC1 (p < 0.01). Root mean square was unchanged in all the instants. The present study showed that adaptation is depicted in the local muscle blood flow and the frequency contents of the EMG after an unaccustomed ECC inducing muscle soreness. These alterations provide a potential mechanism for a rapid adaptation, which decreases susceptibility of the muscle to develop further soreness in the subsequent ECC bout.

On-Ice Functional Assessment of an Elite Ice Hockey Goaltender After Treatment for Femoroacetabular Impingement

Background:Femoroacetabular impingement (FAI) is a major cause of performance inhibition in elite-level athletes. The condition is characterized by pain, osseous abnormalities such as an increased alpha angle, and decreased range of motion at the affected hip joint. Arthroscopic surgical decompression is useful in reshaping the joint to alleviate symptoms. Functional kinematic outcomes of sport-specific movements after surgery, however, are presently unknown.Hypothesis:The ability of an ice hockey goaltender to execute sport-specific movements would improve after arthroscopic surgery.Study Design:Clinical research.Level of Evidence:Level 5.Methods:An ice hockey goaltender was evaluated after arthroscopic correction of FAI on the symptomatic hip. Passive range of motion and radiographic parameters were assessed from a computed tomography–derived 3-dimensional model. An on-ice motion capture system was also used to determine peak femoral shock and concurrent hip joint postures during the butterfly and braking movements.Results:Maximum alpha angles were 47° in the surgical and 61° in the nonsurgical hip. Internal rotation range of motion was, on average, 23° greater in the surgically corrected hip compared with contralateral. Peak shock was lower in the surgical hip by 1.39 g and 0.86 g during butterfly and braking, respectively. At peak shock, the surgical hip demonstrated increased flexion, adduction, and internal rotation for both tasks (butterfly, 6.1°, 12.3°, and 30.8°; braking, 14.8°, 19.2°, and 41.4°).Conclusion:On-ice motion capture revealed performance differences between hips after arthroscopic surgery in a hockey goaltender. Range of motion and the patient’s subjective assessment of hip function were improved in the surgical hip. While presenting as asymptomatic, it was discovered that the contralateral hip displayed measurements consistent with FAI. Therefore, consideration of preemptive treatment in a presently painless hip may be deemed beneficial for young athletes seeking a long career in sport, and future work is needed to determine the costs and benefits of such an approach.Clinical Relevance:Surgical treatment of symptomatic FAI can achieve pain relief and improved kinematics of the hip joint with athletic activities. Additional studies are necessary to determine whether improved kinematics enhance the longevity of the native hip and alter the progression of osteoarthritic changes in those with asymptomatic FAI deformity.

Electromyographic Analysis of Selected Upper Extremity Muscles during Jump Throwing in Handball

The purpose of this study was to determine upper extremity selected muscles activity of throwing performance in handball and work-loading to determine the percentage contribution of the muscles that more activation during throwing performance. Five male high level handball players participated in this study were (age: 20.5 ± 0.53 years; body mass: 81.00 ± 3.16 kg; height: 186.5 ± 3.69 cm). The EMG activity of the selected upper extremity muscles was measured using an 16-channel surface EMG system (ME6000 telemetric hardware system, Mega Electronics Ltd., FINLAND), Bipolar, Ag/AgCl surface electrodes (SKINTACT, FS-521), Innsbruck, Austria) were placed over the motor point of each muscle, and the EMG signals were acquired at a sampling rate of 1000 Hz with the MEGAWIN version 3.1-b12 software. Results showed the activities and arrangement of selected muscles were Deltoid muscle - medial part 1268.20±133.93 (38.70%), Flexor of the wrist 462.00±89.04 (16.30%), Flexor carpi ulnaris 439.30±33.87 (14.40%), Biceps brachii muscle 364.90±31.34 (12.90%), Rectus abdominis muscle 314.80±48.94 (9.70%), and Pectoralis major muscle 225.90±36.70 (8.00%). The rational for using sEMG to study muscle activation during a standardized jump throwing in handball is to provide a better understanding of muscle activation during this sport specific movement and muscle contributions during jump throwing in handball, and these data may be important for handball's coaches to jump throwing performance training.

The effects of sport-specific and minimalist footwear on the kinetics and kinematics of three netball-specific movements

Netball is associated with a high frequency of chronic injuries. There is currently a trend towards the utilisation of minimalist footwear in netball players in lieu of traditional netball trainers. The aim of the current investigation was to examine the influence of netball-specific and minimalist footwear on the kinetics and three-dimensional (3-D) kinematics of three sport specific movements. Twelve female netballers performed three movements, run, cut and vertical jump, whilst wearing a conventional netball trainer and also a minimalist trainer. 3-D kinematics of the lower extremities were measured using an eight-camera motion analysis system alongside kinetic information which was obtained using a force platform. Kinetic/3-D kinematic differences between movements wearing different footwear were examined using paired t-tests. The kinetic analysis revealed that impact parameters were significantly greater in the minimalist footwear in comparison to the netball shoe for all three movements. In addition peak ankle eversion was shown to be significantly greater in the minimalist footwear in the running movement condition. The current study therefore suggests that the utilisation of minimalist footwear for netball training/performance may place netballers at increased risk from chronic injuries based on which a continued utilisation of netball-specific footwear may be recommended.

Small-sided games in team sports training: a brief review.

Small-sided games (SSGs) incorporating skills, sport-specific movements, at intensities sufficient to promote aerobic adaptations, are being increasingly implemented in professional team sport environments. Small-sided games are often employed by coaches based on the premise that the greatest training benefits occur when training simulates the specific movement patterns and physiological demands of the sport. At present, there is relatively little information regarding how SSG can best be used to improve physical capacities and technical and tactical skills in team sports. It is possible that with some modifications (e.g., number of players, pitch size, coach encouragement, and wrestling), such games may be physiologically beneficial for athletes with relatively high initial aerobic fitness levels. For instance, it has been shown that 3-a-side soccer SSG resulted in higher intensity (i.e., greater overall distance, less jogging and walking, higher heart rate, and more tackling, dribbling, goal attempts, and passes) than 5-a-side SSG. Likewise, when player numbers were kept constant, a larger playing area increased the intensity of the SSG with a smaller playing area having the opposite effect. It has also been demonstrated that energy expenditure was similar between badminton and volleyball courts, but lower than that obtained in a basketball court. Moreover, it has been demonstrated in rugby that wrestling can increase the physical demands of SSG. Consistent coach encouragement can also increase training intensity, although most rule changes have trivial or no effect on exercise intensity. Further research is required to examine the optimal periodization strategies of SSG training for the long-term development of physiological capacity, technical skill, and tactical proficiency, while also minimizing the associated risk of injuries.

Overuse Injuries in Youth Football Players

Objectives:Youth football players encounter many injuries especially during the school period when they are trying to make scool and football together. Due to consistent team selection in competetion, school matches, academy leaque matches and age group national team matches, as a result of high intensity training at a young age they are extremely overloaded.Methods:145 football players of 13-19 age group playing in the academy leaque of Bursaspor have been observed for 10 months (Augost 2013-May 2014) ,injuries caused by overuse and that require at least 2 days break from sports activities.Results:Were determined on 45 football players while lower extremities upper group (hamstring, quadriceps)muscles constitued the majority of the injuries; In the adductor region were also seen often. The most striking finding is epiphyses avulsion fractures on the 3 players.Conclusion:There are many risk factors causing injuries releated to overuse in youth athletes.Such as previous injuries,anatomic malalignment,extreme flexibility,loss of bone mineral density,overload to physes,high intensity training,when rest is not adequate, and not appropriate recovery.Limitation of sports specific repetatif movements(eg,pitching limits);scheduled rest periods and recovery time;such modifications to be individualized based upon the sport and the athlete's age,growt rate,readiness;optimal preparation of the preseason conditioning program;well neuromusculer training before workout;exact monitoring of the training and determination of the occasions on which injuries occur are important in preventing such injuries.

Accuracy and Reliability of GPS Devices for Measurement of Sports-Specific Movement Patterns Related to Cricket, Tennis, and Field-Based Team Sports

The aim of this study was to determine the accuracy and reliability of 5, 10, and 15 Hz global positioning system (GPS) devices. Two male subjects (mean ± SD; age, 25.5 ± 0.7 years; height, 1.75 ± 0.01 m; body mass, 74 ± 5.7 kg) completed 10 repetitions of drills replicating movements typical of tennis, cricket, and field-based (football) sports. All movements were completed wearing two 5 and 10 Hz MinimaxX and 2 GPS-Sports 15 Hz GPS devices in a specially designed harness. Criterion movement data for distance and speed were provided from a 22-camera VICON system sampling at 100 Hz. Accuracy was determined using 1-way analysis of variance with Tukey's post hoc tests. Interunit reliability was determined using intraclass correlation (ICC), and typical error was estimated as coefficient of variation (CV). Overall, for the majority of distance and speed measures, as measured using the 5, 10, and 15 Hz GPS devices, were not significantly different (p > 0.05) to the VICON data. Additionally, no improvements in the accuracy or reliability of GPS devices were observed with an increase in the sampling rate. However, the CV for the 5 and 15 Hz devices for distance and speed measures ranged between 3 and 33%, with increasing variability evident in higher speed zones. The majority of ICC measures possessed a low level of interunit reliability (r = -0.35 to 0.39). Based on these results, practitioners of these devices should be aware that measurements of distance and speed may be consistently underestimated, regardless of the movements performed.