Anterior cruciate ligament injury prevention should focus primarily on reduction of the knee abduction moment (KAM) in landing tasks. Gluteus medius and hamstring forces are considered to decrease KAM during landing. The effects of different muscle stimulations on KAM reduction were compared using 2 electrode sizes (standard 38 cm2 and half size 19 cm2) during a landing task. Twelve young healthy female adults (22.3 [3.6] y, 1.62 [0.02] m, 50.2 [4.7] kg) were recruited. KAM was calculated under 3 conditions of muscle stimulation (gluteus medius, biceps femoris, and both gluteus medius, and biceps femoris) using 2 electrode sizes, respectively versus no stimulation during a landing task. A repeated-measures analysis of variance determined that KAM differed significantly among stimulation conditions and post hoc analysis revealed that KAM was significantly decreased in conditions of stimulating either the gluteus medius (P < .001) or the biceps femoris (P < .001) with the standard electrode size, and condition of stimulating both gluteus medius and biceps femoris with half-size electrode (P = .012) when compared with the control condition. Therefore, stimulation on the gluteus medius, the biceps femoris, or both muscles could be implemented for the examination of anterior cruciate ligament injury potential.
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Dan Wang, Man Wang, Vikki Wing-Shan Chu, Patrick Shu-Hang Yung, and Daniel T.P. Fong
Kishor Lakshminarayanan, Rakshit Shah, Yifei Yao, and Deepa Madathil
Previous studies have demonstrated that both visual and proprioceptive feedback play vital roles in mental practice of movements. Tactile sensation has been shown to improve with peripheral sensory stimulation via imperceptible vibratory noise by stimulating the sensorimotor cortex. With both proprioception and tactile sensation sharing the same population of posterior parietal neurons encoding within high-level spatial representations, the effect of imperceptible vibratory noise on motor imagery-based brain–computer interface is unknown. The objective of this study was to investigate the effects of this sensory stimulation via imperceptible vibratory noise applied to the index fingertip in improving motor imagery–based brain–computer interface performance. Fifteen healthy adults (nine males and six females) were studied. Each subject performed three motor imagery tasks, namely drinking, grabbing, and flexion–extension of the wrist, with and without sensory stimulation while being presented a rich immersive visual scenario through a virtual reality headset. Results showed that vibratory noise increased event-related desynchronization during motor imagery compared with no vibration. Furthermore, the task classification percentage was higher with vibration when the tasks were discriminated using a machine learning algorithm. In conclusion, subthreshold random frequency vibration affected motor imagery–related event-related desynchronization and improved task classification performance.
Adapted Physical Activity Quarterly
Adapted Physical Activity Quarterly
Adapted Physical Activity Quarterly
Mark Jankowski, Sarah Partington, Nick Heather, and Elizabeth Partington
The purpose of this study was to provide new knowledge about the temporal and contextual aspects of the alcohol–sport relationship. Eight U.K. student-athletes completed the Alcohol Use Disorders Identification Test in their final year at university, 18 months, and 30 months after graduation. They also completed semistructured interviews about their drinking motives, behaviors, and life circumstances. Results showed that participants reduced their alcohol consumption after leaving university, but despite the onset of some adult responsibilities, most were still drinking at hazardous levels. After university, drinking took place with old friends, new colleagues, and new sporting teammates. At all time points, social drinking motives were the most prevalent. Findings demonstrate a relationship between alcohol and sport that is cemented at university but continues beyond it. Targeted interventions to reduce the role of alcohol in the social experience of sport are needed to support long-term athlete health.
Brantley K. Ballenger, Emma E. Schultz, Melody Dale, Bo Fernhall, Robert W. Motl, and Stamatis Agiovlasitis
This systematic review examined whether physical activity interventions improve health outcomes in adults with Down syndrome (DS). We searched PubMed, APA PsycInfo, SPORTDiscus, APA PsycARTICLES, and Psychology and Behavioral Sciences Collection using keywords related to DS and physical activity. We included 35 studies published in English since January 1, 1990. Modes of exercise training programs included aerobic exercise, strength training, combined aerobic and strength training, aquatic, sport and gaming, and aerobic and strength exercise interventions combined with health education. The evidence base indicates that aerobic and strength exercise training improve physical fitness variables including maximal oxygen uptake, maximal heart rate, upper and lower body strength, body weight, and body fat percentage. Sport and gaming interventions improve functional mobility, work task performance, and sport skill performance. We concluded that adults with DS can accrue health benefits from properly designed physical activity and exercise interventions.
Fernanda Metzen, João Breno Ribeiro-Alvares, Klauber Dalcero Pompeo, Francesca Chaida Sonda, Rodrigo Silva Santos, and Marco Aurélio Vaz
Développé à la seconde is a classic ballet movement that requires the maintenance of a high hip joint range of motion (ROM) and muscle strength. However, the contribution of these hip joint biomechanical parameters to this movement’s esthetic performance is unclear. Therefore, this study evaluated hip joint biomechanical characteristics of 21 experienced ballet dancers (15–29 y old) and verified the relationship between these variables with the développé à la seconde static and dynamic performance. Correlations between age, ballet practice time, gluteus maximus and gluteus medius thicknesses, ROM, and muscle strength with absolute and relative static and dynamic performances were verified. Flexors, extensors, and internal rotators peak strength and external rotation ROM were highly correlated with absolute and relative static performances (0.5–0.7). Flexors and extensors strength and external and internal rotation ROM showed the highest correlations with the développé dynamic performance (0.49–0.67). Flexor strength and flexor and internal rotation ROM predicted 26% to 41% of this movement’s static and dynamic performances. Thus, from a biomechanical perspective, clinical assessment of hip strength and ROM may be used to predict the quality of the ballet dancers’ performance of the développé à la seconde and guide classical ballet training.
Lawrence P. Behmer Jr., Mathew J.C. Crump, and Kelly J. Jantzen
Several computational models make predictions about the activation states of individual elements of an action sequence during planning and execution; however, the neural mechanisms of action planning are still poorly understood. Simple chaining models predict that only the first response in an action sequence should be active during planning. Conversely, some parallel activation models suggest that during planning, a serial inhibition process places the individual elements of the action into a serial order across a winner-takes-all competitive choice gradient in which earlier responses are more active, and hence likely to be selected for execution compared with later responses. We triggered transcranial magnetic stimulation pulses at 200 or 400 ms after the onset of a five-letter word, in which all but one response was planned and typed with the left hand, except for a single letter which required a right index finger response exclusively at one of five serial positions. We measured the resulting motor-evoked potentials at the right index finger as a marker for the activation state of that planned response. We observed no difference in motor-evoked potential amplitude across any serial position when a right index finger response was planned at 200 ms after the onset of the word; however, we observed a graded pattern of activation at 400 ms, with earlier positions that required a right index finger response showing greater motor-evoked potentials amplitude compared with later positions. These findings provide empirical support for competitive queuing computational models of action planning.
