Jaap van Dieen
Alejandro Pérez-Castilla, Ainara Jiménez-Alonso, Mar Cepero, Sergio Miras-Moreno, F. Javier Rojas and Amador García-Ramos
This study explored the impact of different frequencies of knowledge of results (KR) on velocity performance during ballistic training. Fifteen males completed four identical sessions (three sets of six repetitions at 30% one-repetition maximum during the countermovement jump and bench press throw) with the only difference of the KR condition provided: no feedback, velocity feedback after the first half of repetitions of each set (HalfKR), velocity feedback immediately after each repetition (ImKR), and feedback of the average velocity of each set (AvgKR). When compared with the control condition, the ImKR reported the highest velocity performance (1.9–5.3%), followed by the HalfKR (1.3–3.6%) and AvgKR (0.7–4.3%). These results support the verbal provision of velocity performance feedback after every repetition to induce acute improvements in velocity performance.
Daniel Viggiani, Erin M. Mannen, Erika Nelson-Wong, Alexander Wong, Gary Ghiselli, Kevin B. Shelburne, Bradley S. Davidson and Jack P. Callaghan
People developing transient low back pain during standing have altered control of their spine and hips during standing tasks, but the transfer of these responses to other tasks has not been assessed. This study used video fluoroscopy to assess lumbar spine intervertebral kinematics of people who do and do not develop standing-induced low back pain during a seated chair-tilting task. A total of 9 females and 8 males were categorized as pain developers (5 females and 3 males) or nonpain developers (4 females and 5 males) using a 2-hour standing exposure; pain developers reported transient low back pain and nonpain developers did not. Participants were imaged with sagittal plane fluoroscopy at 25 Hz while cyclically tilting their pelvises anteriorly and posteriorly on an unstable chair. Intervertebral angles, relative contributions, and anterior–posterior translations were measured for the L3/L4, L4/L5, and L5/S1 joints and compared between sexes, pain groups, joints, and tilting directions. Female pain developers experienced more extension in their L5/S1 joints in both tilting directions compared with female nonpain developers, a finding not present in males. The specificity in intervertebral kinematics to sex-pain group combinations suggests that these subgroups of pain developers and nonpain developers may implement different control strategies.
Byungmo Ku, Megan MacDonald, Bridget Hatfield and Kathy Gunter
The purpose of this study was to test a modified conceptual model of the associations between parental supports and physical activity (PA) orientations and the PA behaviors of young children with developmental disabilities (DDs). In total, 135 parents of young children with DDs completed a questionnaire, which consisted of 67 questions. A pathway analysis indicated that tangible and intangible parental supports were significantly associated with PA behaviors in young children with DDs (β = 0.26, p = .01, and β = 0.24, p = .02, respectively). Tangible parental support was positively associated with parents’ PA behaviors and PA enjoyment (β = 0.22, p < .001, and β = 0.13, p = .04, respectively). Intangible parental support was positively associated with parents’ PA behaviors and PA importance (β = 0.19, p = .05, and β = 0.33, p < .001, respectively). In addition, parental PA behaviors and parents’ perceptions of their children’s motor performance were both directly associated with PA behaviors in young children with DDs. These results highlight the importance of parental support and PA orientations in relation to the PA behaviors of young children with DDs.
Fabio Bertapelli, Ken Pitetti, Ruth A. Miller, Adam Jaeger, Michael Loovis, Wilson D. do Amaral-Junior, Marcos M. de Barros-Filho and Gil Guerra-Junior
Youth with intellectual disabilities (IDs) demonstrate below-criteria motor competence (MC) compared with typically developing (TD) youth. Whether differences in MC exist for youth with ID from different countries is unknown. This study examined the MC of youth with ID from Brazil (BR) and the United States (US) and compared it with norms for TD youth as established by the Bruininks–Oseretsky Test of Motor Proficiency (BOT-2). The authors measured 19 BOT-2 test items for bilateral coordination, balance, and upper limb coordination of 502 youth (BR = 252, US = 250) with ID (6–21 years). Raw scores were converted to %ceiling (percentile of highest expected scores). For all test items, no significant differences were seen between BR and US participants in %ceiling scores. Participants from both countries demonstrated equivalent to slightly below BOT-2 norms in 14 of the 19 test items, with lowest scores seen in contralateral synchronizing bilateral coordination, balancing on one leg, and ball handling.
Jayshree Shah, Tarushi Tanwar, Iram Iram, Mosab Aldabbas and Zubia Veqar
The objective was to investigate the electromyographic activity of the lumbar multifidus (MF) muscle and longissimus thoracis muscle, along with their activity ratio (MF longissimus thoracis ratio), during quadruped stabilization exercise performed with neutral posture and with increased lumbar lordosis in patients with chronic low back pain (CLBP). A total of 23 patients with CLBP (12 females and 11 males) were recruited based on inclusion and exclusion criterion. Each patient performed 4 exercises in random order, with surface electromyography electrodes and an electrogoniometer attached. A cross-sectional study design was used to measure the amplitude of muscle activation (as a percentage of maximum voluntary contraction) in each patient across the 2 muscles (MF and longissimus thoracis) during quadruped stabilization exercise with neutral posture and with increased lumbar lordosis. A 2-way analysis of variance was conducted, which demonstrated a statistically significant increase in the recruitment of MF with increased lumbar lordosis in patients with CLBP during quadruped exercise. An increase of 9.7% and 16.9% maximum voluntary contraction in MF electromyographic activity was observed in lumbar lordosis posture during the quadruped leg raise and quadruped leg-arm raise exercise, respectively (P < .01), when compared to the neutral posture. The increased recruitment of MF with lumbar lordosis in the quadruped position has strong implications in the assessment and management of patients with CLBP.
Angelica E. Lang, Soo Y. Kim, Stephan Milosavljevic and Clark R. Dickerson
Breast cancer survivors have known scapular kinematic alterations that may be related to the development of secondary morbidities. A measure of muscle activation would help understand the mechanisms behind potential harmful kinematics. The purpose of this study was to define muscle force strategies in breast cancer survivors. Shoulder muscle forces during 6 functional tasks were predicted for 25 breast cancer survivors (divided by impingement pain) and 25 controls using a modified Shoulder Loading Analysis Module. Maximum forces for each muscle were calculated, and 1-way analysis of variance (P < .05) was used to identify group differences. The differences between maximum predicted forces and maximum electromyography were compared with repeated-measures analysis of variance (P < .05) to evaluate the success of the model predictions. Average differences between force predictions and electromyography ranged from 7.3% to 31.6% but were within the range of previously accepted differences. Impingement related pain in breast cancer survivors is associated with increased force of select shoulder muscles. Both pectoralis major heads, upper trapezius, and supraspinatus peak forces were higher in the pain group across all tasks. These force prediction differences are also associated with potentially harmful kinematic strategies, providing a direction for possible rehabilitation strategies.
Justin A. Haegele, Chunxiao Li and Wesley J. Wilson
The purpose of this study was to examine the relationship between interpersonal/intrapersonal mindfulness, contact anxiety, and attitudes toward students with visual impairments among certified adapted physical educators. Participants included 115 certified adapted physical educators who completed a 31-item online survey, composed of a 10-item demographic questionnaire, a 14-item mindfulness in teaching scale, a four-item intergroup anxiety scale, and a three-item attitude scale. Hierarchical multiple regression analyses revealed that intrapersonal mindfulness was a negative predictor of contact anxiety (β = −0.26, p = .007) and contact anxiety negatively predicted attitudes (β = −0.22, p = .02). A mediation analysis revealed that intrapersonal mindfulness had an indirect effect on attitudes through contact anxiety, b = 0.09, SE = 0.05, 95% confidence interval [0.006, 0.22]. Collectively, both intrapersonal and interpersonal mindfulness appear to be responsible for the formation of attitudes, but with different underlying processes involved.
Irineu Loturco, Michael R. McGuigan, Valter P. Reis, Sileno Santos, Javier Yanci, Lucas A. Pereira and Ciro Winckler
This study aimed to investigate the association between the optimum power load in the bench press (BP), shoulder press (SP), and prone bench pull (PBP) exercises and acceleration (ACC) and speed performances in 11 National Team wheelchair basketball (WB) players with similar levels of disability. All athletes were previously familiarized with the testing procedures that were performed on the same day during the competitive period of the season. First, athletes performed a wheelchair 20-m sprint assessment and, subsequently, a maximum power load test to determine the mean propulsive power (MPP) in the BP, SP, and PBP. A Pearson product–moment correlation was used to examine the relationships between sprint velocity (VEL), ACC, and the MPP in the three exercises. The significance level was set as p < .05. Large to very large significant associations were observed between VEL and ACC and the MPP in the BP, SP, and PBP exercises (r varying from .60 to .77; p < .05). The results reveal that WB players who produce more power in these three exercises are also able to accelerate faster and achieve higher speeds over short distances. Given the key importance of high and successive ACCs during wheelchair game-related maneuvers, it is recommended that coaches frequently assess the optimum power load in BP, SP, and PBP in WB players, even during their regular training sessions.
Erika M. Pliner, April A. Dukes, Kurt E. Beschorner and Arash Mahboobin
There is a need for pedagogical techniques that increase student engagement among underrepresented groups in engineering. Relating engineering content to student interests, particularly through biomechanics applications, shows promise toward engaging a diverse group of students. This study investigates the effects of student interests on engagement and performance in 10th grade students enrolled in a summer program for students underrepresented in the science, technology, engineering, and mathematics fields. The authors assessed the effects of interest-tailored lectures on student engagement and performance in a 5-week program with bioengineering workshops, focusing on the delivery of biomechanics content. A total of 31 students received interest-tailored lectures (intervention) and 23 students received only generic lectures (control) in biomechanics. In addition, the authors assessed the effects of teaching method (lecture, classroom activities, and laboratory tours) on student engagement. The authors found interest-tailored lectures to significantly increase student engagement in lecture compared with generic lectures. Students that received interest-tailored lectures had an insignificant, but meaningful 5% increase in student performance. Students rated laboratory tours higher in engagement than other teaching methods. This study provides detailed examples that can directly assist student teaching and outreach in biomechanics. Furthermore, the pedagogical techniques in this study can be used to increase engagement of underrepresented students in engineering.