Micheal J. Luera, Brittany Dowling, Tyler W.D. Muddle, and Nathaniel D.M. Jenkins
Pitch velocity (PV) is important for pitching success, and the pelvis and trunk likely influence pitch performance. The purposes of this study were to examine the differences in pelvis and trunk kinetics and kinematics in professional baseball pitchers who throw at lower versus higher velocities (HVPs) and to examine the relationships among pelvis and trunk kinetics and kinematics and PV during each phase of the pitch delivery. The pitch velocity, pelvis and trunk peak angular velocities, kinetic energies and torques, and elbow and shoulder loads were compared among HVPs (n = 71; PV ≥ 40.2 m/s) and lower velocities pitchers (n = 78; PV < 39.8 m/s), as were trunk and pelvis rotation, flexion, and obliquity among 7 phases of the pitching delivery. Relationships among the kinetic and kinematic variables and PVs were examined. Higher velocity pitchers achieved greater upper trunk rotation at hand separation (+7.2°, P < .001) and elbow extension (+5.81°, P = .002) and were able to generate greater upper trunk angular velocities (+36.6 m/s, P = .01) compared with lower velocity pitcher. Trunk angular velocity (r = .29) and upper trunk rotation at hand separation (r = .18) and foot contact (r = .17) were weakly related to PV. Therefore, HVPs rotate their upper trunk to a greater degree during the early phases of the pitching motion and subsequently generate greater trunk angular velocities and PV.
Piaolin Peng, Shaolan Ding, Zhikang Wang, Yifan Zhang, and Jiahao Pan
The purpose of this study was to explore the immediate effects of running speed and midsole type on foot loading during heel–toe running. Fifteen healthy male college students were required to complete 3 running trials on an indoor 45-m tartan runway at 4 different speeds (3, 4, 5, and 6 m/s) using 2 different running footwear types (engineering thermoplastic polyurethane elastomer, polyurethane elastomer; and ethylene vinyl acetate, vinyl acetate). The ground reaction force and plantar pressure data were quantified. Significant speed effects were detected both in ground reaction force and plantar pressure-related data (P < .05). Vertical average loading rate was significantly less, and time to first peak occurred later for the polyurethane elastomer compared with vinyl acetate footwear (P < .05). The peak pressure of the heel, medial forefoot, central forefoot, lateral forefoot, and big toe was significantly less when subjects wore a polyurethane elastomer than vinyl acetate footwear (P < .05). Overall, our results suggested that, compared with the vinyl acetate footwear, the special polyurethane elastomer footwear that is adhered with thousands of polyurethane elastomer granules was effective at reducing the mechanical impact on the foot.
Johanna S. Rosén, Victoria L. Goosey-Tolfrey, Keith Tolfrey, Anton Arndt, and Anna Bjerkefors
The purpose of this study was to examine the interrater reliability of a new evidence-based classification system for Para Va'a. Twelve Para Va'a athletes were classified by three classifier teams each consisting of a medical and a technical classifier. Interrater reliability was assessed by calculating intraclass correlation for the overall class allocation and total scores of trunk, leg, and on-water test batteries and by calculating Fleiss’s kappa and percentage of total agreement in the individual tests of each test battery. All classifier teams agreed with the overall class allocation of all athletes, and all three test batteries exhibited excellent interrater reliability. At a test level, agreement between classifiers was almost perfect in 14 tests, substantial in four tests, moderate in four tests, and fair in one test. The results suggest that a Para Va'a athlete can expect to be allocated to the same class regardless of which classifier team conducts the classification.
Byron Lai, Eunbi Lee, Mayumi Wagatsuma, Georgia Frey, Heidi Stanish, Taeyou Jung, and James H. Rimmer
This scoping review synthesized reviews of physical activity (PA) interventions for children and youth with disabilities to highlight promising elements of effective interventions, research methodological limitations, and research priorities. Twenty studies were eligible and underwent three rounds of review by an expert panel. Rich and diverse PA programs derived potential short-term benefits toward health, function, and PA. Strategies to increase sample sizes included embedding programs in the community and using information communication technology to deliver exercise programs. Methodological limitations of interventions included a lack of generalizability, transferability, and scientific rigor. Three research priorities were identified: develop and report precision-based intervention strategies, identify strategies that promote both long-term and sustainable PA participation and outcomes, and develop scalable interventions and recruitment strategies. If addressed, these areas could enhance the impact of PA interventions for children and youth with disabilities.
Amanda Ebert and Donna L. Goodwin
Adapted physical activity (APA) practitioners are encouraged to be reflexive practitioners, yet little is known about the moral dilemmas faced as they instruct inclusive physical activity or fitness programs. Professional landscape tensions may arise when diverse organizational demands, policies, traditions, and values merge. The study purpose was to explore how APA professionals experience and resolve moral discomfort in professional practice. Using interpretative phenomenological analysis, seven APA professionals completed one-on-one semistructured interviews. The conceptual framework of relational ethics facilitated deep engagement with the professionals’ stories of navigating the ethical minefields of their practice. Four themes were developed from the thematic interpretative phenomenological analysis: The ass(et) of vulnerability, Friends or friendly? “We are fucked either way,” and Now what? Grappling with discomfort. The moral discomfort and strategies for resolution described by APA professionals highlighted the need for judgment-free pedagogical spaces where taken-for-granted practices can be contemplated and discussed.
Melanie B. Lott and Gan Xu
Despite the prevalence of turning maneuvers in everyday life, relatively little research has been conducted on joint angle kinematic coordination during whole-body rotations around a vertical axis. Ballet pirouettes provide an opportunity to study dynamically balanced, whole-body rotations on a single support and the potential to scale results to smaller angular displacements executed by general populations. The purpose of this study was to determine the supporting limb’s ankle, knee, hip, and pelvis-trunk joint angle excursions and kinematic coordination strategies utilized during the pirouette’s turn phase. Advanced dancers (n = 6) performed pirouettes while whole-body 3-dimensional kinematics were recorded. Group mean ankle ab/adduction excursion was significantly greater than all other excursions (P < .05). Principal components analysis was applied to joint angle time-series data (4 joints × 3 degrees of freedom = 12 variables). The first 4 principal components explained 92% (2%) of variance, confirming redundancy in joint angle data. Evolution of the data along the first principal component in successful pirouettes oscillated at the pirouette’s rotational frequency. Principal component eigenvector coefficients provided evidence of ankle–hip coordination, although specific coordination patterns varied between individuals and across trials. These results indicate that successful pirouettes are executed with continuous, oscillatory joint angle coordination patterns.
Jake A. Melaro, Ramzi M. Majaj, Douglas W. Powell, Paul DeVita, and Max R. Paquette
Aging is associated with a distal-to-proximal shift in joint kinetics during walking. This plasticity of gait is amplified rather than attenuated in old adults with high physical capacity. Because running is associated with greater kinetic demands at the ankle, older individuals with more versus less lifetime running exposure may retain a larger proportion of their ankle kinetics. The purpose of the study was to compare lower-extremity joint kinetics during walking between middle-aged runners with high and low lifetime running exposure. Eighteen middle-aged runners (9 per group) participated. Joint kinetics were calculated from kinematic and ground reaction force data during overground walking at 1.3 m·s−1 and compared between groups. High exposure runners produced 50% greater positive hip work (P = .03; Cohen d = 1.02) during walking compared with low exposure runners, but ankle kinetics were not different between groups. No other differences in joint kinetics or kinematics were observed between groups. These findings suggest that the age-related increase in hip joint kinetics during walking could be a compensatory gait strategy that is not attenuated by lifetime running exposure alone. Finally, the amount of lifetime running exposure did not affect ankle kinetics during walking in middle-aged runners.