The effect of subconcussive impacts on balance are not well known. The purpose of this study is to determine the effect of subconcussive impacts on dynamic balance over the course of a rugby season. Significant negative linear correlations were found between total peak linear acceleration and dominant leg (r = −.585, p = .046) and bilateral score (r = −.615, p = .033); also between total impacts over 10g and dominant leg (r = −.653, p = .021), nondominant leg (r = −.687, p = .014), and the combined total (r = −.731, p = .007). Results indicate subconcussive impacts may affect dynamic balance over the course of a competitive season of women’s collegiate rugby.
Eric Schussler, Ryan S. McCann, Nicholas Reilly, Thomas R. Campbell, and Jessica C. Martinez
Allison H. Gruber, Shuqi Zhang, Jiahao Pan, and Li Li
The running footwear literature reports a conceptual disconnect between shoe cushioning and external impact loading: footwear or surfaces with greater cushioning tend to result in greater impact force characteristics during running. Increased impact loading with maximalist footwear may reflect an altered lower-extremity gait strategy to adjust for running in compliant footwear. The authors hypothesized that ankle and knee joint stiffness would change to maintain the effective vertical stiffness, as cushioning changed with minimalist, traditional, and maximalist footwear. Eleven participants ran on an instrumental treadmill (3.5 m·s−1) for a 5-minute familiarization in each footwear, plus an additional 110 seconds before data collection. Vertical, leg, ankle, and knee joint stiffness and vertical impact force characteristics were calculated. Mixed model with repeated measures tested differences between footwear conditions. Compared with traditional and maximalist, the minimalist shoes were associated with greater average instantaneous and average vertical loading rates (P < .050), greater vertical stiffness (P ≤ .010), and less change in leg length between initial contact and peak resultant ground reaction force (P < .050). No other differences in stiffness or impact variables were observed. The shoe cushioning paradox did not hold in this study due to a similar musculoskeletal strategy for running in traditional and maximalist footwear and running with a more rigid limb in minimalist footwear.
Sadie Rose Adado and Kenneth E. Games
Integrative patient-centered care (PCC) models encompass all dimensions of the patient, including physical well-being, evidence-based shared decision making, and determinants of health as they relate to quality of life. The purpose of this study was to explore parental experiences with the principles of PCC, related to the healthcare of their dependent after interactions with a provider. Using an observational design, our results demonstrated that parents of adolescent athletes rated PCC concepts as “very important” and the care delivered in relation to PCC by providers as “very effective.” PCC is perceived as valuable to parents, and therefore, athletic trainers must continue to develop and integrate PCC in the delivery of care within their clinical practice.
Timothy L. Miller and Rose Backs
Presented here is the case of a 16-year-old male cross-country runner with chronic leg pain who was diagnosed with popliteal artery entrapment syndrome. An extensive workup was performed on the athlete that eventually included a postexercise arteriogram to reach the diagnosis. Ultimately the athlete’s symptoms required him to undergo bilateral leg surgeries to decompress the popliteal arteries. Extensive collaboration between athletic trainers, physical therapists, orthopedic surgery, sports medicine, and vascular surgery was required to treat the athlete’s condition and return him to distance running.
Patrick D. Fischer, Keith A. Hutchison, James N. Becker, and Scott M. Monfort
Cognitive function plays a role in understanding noncontact anterior cruciate ligament injuries, but the research into how cognitive function influences sport-specific movements is underdeveloped. The purpose of this study was to determine how various cognitive tasks influenced dual-task jump-landing performance along with how individuals’ baseline cognitive ability mediated these relationships. Forty female recreational soccer and basketball players completed baseline cognitive function assessments and dual-task jump landings. The baseline cognitive assessments quantified individual processing speed, multitasking, attentional control, and primary memory ability. Dual-task conditions for the jump landing included unanticipated and anticipated jump performance, with and without concurrent working memory and captured visual attention tasks. Knee kinematics and kinetics were acquired through motion capture and ground reaction force data. Jumping conditions that directed visual attention away from the landing, whether anticipated or unanticipated, were associated with decreased peak knee flexion angle (P < .001). No interactions between cognitive function measures and jump-landing conditions were observed for any of the biomechanical variables, suggesting that injury-relevant cognitive-motor relationships may be specific to secondary task demands and movement requirements. This work provides insight into group- and subject-specific effects of established anticipatory and novel working memory dual-task paradigms on the neuromuscular control of a sport-specific movement.
Karini Borges dos Santos, Paulo Cesar Barauce Bento, Carl Payton, and André Luiz Felix Rodacki
This study described the kinematic variables of disabled swimmers’ performance and correlated them with their functional classification. Twenty-one impaired swimmers (S5–S10) performed 50-m maximum front-crawl swimming while being recorded by four underwater cameras. Swimming velocity, stroke rate, stroke length, intracycle velocity variation, stroke dimensions, hand velocity, and coordination index were analyzed. Kendall rank was used to correlate stroke parameters and functional classification with p < .05. Swimming velocity, stroke length, and submerged phase were positively correlated with the para swimmers functional classification (.61, .50, and .41; p < .05, respectively), while stroke rate, velocity hand for each phase, coordination index, and intracyclic velocity variation were not (τ between −.11 and .45; p > .05). Thus, some objective kinematic variables of the impaired swimmers help to support current classification. Improving hand velocity seems to be a crucial point to be improved among disabled swimmers.
Neil Chapman, John William Whitting, Suzanne Broadbent, Zachary Crowley-McHattan, and Rudi Meir
Hamstring strain injuries are common in sport. Supramaximal eccentric or high-intensity isometric contractions are favored in hamstring strain injury prevention. The effect of combining these contraction modes in such prevention programs as a poststretch isometric contraction is unknown. Poststretch isometric contractions incorporate an active stretch and result in greater final isometric force than isometric contractions at comparable joint angles. This study compared torque and muscle activation levels between maximal voluntary isometric contraction and maximal poststretch isometric contractions of the knee flexors. Participants (n = 9) completed baseline maximal voluntary isometric contraction at 150° knee flexion and maximal poststretch isometric contractions at 120° knee flexion actively stretching at 60°/s to 150° knee flexion for final isometric contraction. Torque of the knee flexors and surface electromyography root mean square (sEMGRMS) of biceps femoris long head were simultaneously recorded and compared between baseline and poststretch isometric at 150° knee flexion. Torque was 14% greater in the poststretch isometric condition compared with baseline maximal voluntary isometric contraction (42.45 [20.75] N·m, 14% [22.18%], P < .001) without increase in sEMGRMS of biceps femoris long head (−.03 mV, ±.06, P = .130, d = .93). Poststretch isometric contractions resulted in supramaximal levels of poststretch isometric torque without increased activation of biceps femoris long head.
David R. Howell, Corrine N. Seehusen, Mathew J. Wingerson, Julie C. Wilson, Robert C. Lynall, and Vipul Lugade
Our purpose was to investigate the reliability and minimal detectable change characteristics of a smartphone-based assessment of single- and dual-task gait and cognitive performance. Uninjured adolescent athletes (n = 17; mean age = 16.6, SD = 1.3 y; 47% female) completed assessments initially and again 4 weeks later. The authors collected data via an automated smartphone-based application while participants completed a series of tasks under (1) single-task cognitive, (2) single-task gait, and (3) dual-task cognitive-gait conditions. The cognitive task was a series of continuous auditory Stroop cues. Average gait speed was consistent between testing sessions in single-task (0.98, SD = 0.21 vs 0.96, SD = 0.19 m/s; P = .60; r = .89) and dual-task (0.92, SD = 0.22 vs 0.89, SD = 0.22 m/s; P = .37; r = .88) conditions. Response accuracy was moderately consistent between assessments in single-task standing (82.3% accurate, SD = 17.9% vs 84.6% accurate, SD = 20.1%; P = .64; r = .52) and dual-task gait (89.4% accurate, SD = 15.9% vs 85.8% accurate, SD = 20.2%; P = .23; r = .81) conditions. Our results indicate automated motor-cognitive dual-task outcomes obtained within a smartphone-based assessment are consistent across a 1-month period. Further research is required to understand how this assessment performs in the setting of sport-related concussion. Given the relative reliability of values obtained, a smartphone-based evaluation may be considered for use to evaluate changes across time among adolescents, postconcussion.
John R. Harry, John Krzyszkowski, Luke D. Chowning, and Kristof Kipp
This study sought to identify potential predictors of standing long jump (SLJ) performance using force–time strategy metrics within the unloading, eccentric yielding, eccentric braking, and concentric phases. Fifteen National Collegiate Athletic Association division 1 male soccer players (19  y, 1.81 [0.94] m, 80.3 [22.4] kg) performed 3 maximum-effort SLJs, while 3-dimensional ground reaction force (GRF) data were obtained. Regularized regression models were used to investigate associations between force–time strategy metrics and 2 metrics of SLJ performance (ie, jump distance and modified reactive strength index). Jump height and eccentric yielding time were the only predictors of jump distance that also demonstrated large correlations to jump distance. Anterior–posterior unloading yank, average concentric vertical force, and concentric phase duration were the only predictors of modified reactive strength index that also demonstrated large correlations to modified reactive strength index. To maximize SLJ distance in high-level soccer athletes, human performance practitioners could design interventions to drive changes in strategy to increase jump height and decrease eccentric yielding time. To improve SLJ explosiveness, interventions to drive changes in unloading and concentric force application and decrease concentric time could be emphasized. Importantly, unique variable combinations can be targeted when training for SLJ distance and explosiveness adaptations.
Michelle A. Sandrey
Abstract: Postural distortions in the upper limb are prevalent and change the anatomical alignment, which alters force couples and the biomechanics of the body. Forward head posture (FHP) and rounded shoulder posture (RSP) are the two that are most prevalent. Measurement techniques using the craniovertebral angle for FHP and forward shoulder angle for RSP have been used both clinically and in the literature. However, what is not known is what specific criteria can be consistently used to define FHP and RSP as reference angles lack vigorous validity and there is a shortage of quantity, quality, and consistency of the evidence. Thus, there is much to be learned about postural classifications and the effect on the kinetic chain, supporting the need for further research in this area. As it is important to classify those who may need exercise and therapeutic intervention, following evidence-informed practice to inform decision-making clinicians should continue to evaluate posture, as well as examine scapular kinematics and muscle activity and the effects of interventions to improve posture. Therefore, determining whether FHP and RSP are present is paramount for the treatment to be successful.