Athletes who train on unstable compared to stable surfaces exhibit unique postural control strategies in response to balance perturbations

Background:Athletes have been shown to exhibit better balance compared to non-athletes(NON).However,few studies have investigated how the surface on which athletes train affects the strategies adopted to maintain balance.Two distinct athlete groups who experience different types of sport-specific balance training are stable surface athletes(SSA) such as basketball players and those who train on unstable surfaces(USA) such as surfers.The purpose of this study was to investigate the effects of training surface on dynamic balance in athletes compared to NON.Methods:Eight NON,eight SSA,and eight USA performed five 20-s trials in each of five experimental conditions including a static condition and four dynamic conditions in which the support surface translated in the anteroposterior(AP) or mediolateral(ML) planes using positive or negative feedback paradigms.Approximate entropy(Ap En) and root mean square distance(RMS) of the center of pressure(Co P) were calculated for the AP and ML directions.Four 3 × 5(group × condition) repeated measures ANOVAs were used to determine significant effects of group and condition on variables of interest.Results:USA exhibited smaller Ap En values than SSA in the AP signals while no significant differences were observed in the ML Co P signals.Generally,the negative feedback conditions were associated with significantly greater RMS values than the positive feedback conditions.Conclusion:USA exhibit unique postural strategies compared to SSA.These unique strategies seemingly exhibit a direction-specific attribute and may be associated with divergent motor control strategies.

Baseball pitching kinematics,joint loads,and injury prevention

There is a need for the prevention of upper extremity injuries that affect a large number of competitive baseball players.Currently available evidence alludes to three possible ways to prevent these injuries:1) regulation of unsafe participation factors,2) implementation of exercise intervention to modify suboptimal physical characteristics,and 3) instructional intervention to correct improper pitching techniques.Of these three strategies,instruction of proper pitching technique is under-explored as a method of injury prevention.Therefore,the purpose of this review was to explore the utility of pitching technique instruction in prevention of pitching-related upper extremity injuries by presenting evidence linking pitching technique and pitching-related upper extremity injuries,as well as identifying considerations and potential barriers in pursuing this approach to prevent injuries.Various kinematic parameters measured using laboratory-based motion capture system have been linked to excessive joint loading,and thus pitching-related upper extremity injuries.As we gain more knowledge about the influence of pitching kinematics on joint loading and injury risk,it is important to start exploring ways to modify pitching technique through instruction and feedback while considering the specific skill components to address,mode of instruction,target population,duration of program,and ways to effectively collaborate with coaches and parents.

Potential neurophysiological and biomechanical risk factors for sport-related back problems:A scoping review

This scoping review aims(1)to map the literature dealing with neurophysiological and biomechanical aspects of back problems in athletes in order to identify valid risk-factors for their prevention,plus(2)to identify gaps in the existing research and propose suggestions for future studies.A literature search conducted with Scopus,Web of Science,MEDLINE and Cochrane Library was completed by Elsevier,SpringerLink and Google Scholar.The main neurophysiological risk factors identified leading to back problems in athletes are neuromuscular imbalance,increased muscle fatigability,muscle dysfunction and impaired motor control,whilst biomechanical risk factors include maladaptive spinal,spinopelvic and lower limb kinematics,side-to-side imbalances in axial strength and hip rotation range of motion,spinal overloading and deficits in movement pattern.However,most studies focused on back pain in the lumbar region,whereas less attention has been paid to thoracic and cervical spine problems.The range of sports where this topic has been studied is relatively small.There is a lack of research in sports in which the core muscles are highly involved in specific movements such as lifting weights or trunk rotations.A limited number of studies include female athletes and master athletes of both genders.In addition to chronic back pain patients,it is equally important to conduct research on healthy athletes with a predisposition to spine problems.Investigators should focus their empirical work on identifying modifiable risk factors,predict which athletes are at risk for back problems,and develop personalized sport-specific assessment tools and targeted prevention strategies for them.