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Denys Batista Campos, Isabella Christina Ferreira, Matheus Almeida Souza, Macquiden Amorim Jr, Leonardo Intelangelo, Gabriela Silveira-Nunes, and Alexandre Carvalho Barbosa

Objective: To examine the selective influences of distinct acceleration profiles on the neuromuscular efficiency, force, and power during concentric and eccentric phases of isoinertial squatting exercise. Design: Cross-sectional study. Setting: Biomechanics laboratory of the university. Participants: A total of 38 active adults were divided according to their acceleration profiles: higher (n = 17; >2.5 m/s2) and lower acceleration group (n = 21; <2.5 m/s2). Intervention: All subjects performed squats until failure attached to an isoinertial conic pulley device monitored by surface electromyography of rectus femoris, vastus medialis, vastus lateralis, biceps femoris, and semitendinosus. Main Outcome Measures: An incremental optical encoder was used to assess maximal and mean power and force during concentric and eccentric phases. The neuromuscular efficiency was calculated using the mean force and the electromyographic linear envelope. Results: Between-group differences were observed for the maximal and mean force (P range = .001–.005), power (P = .001), and neuromuscular efficiency (P range = .001–.03) with higher significant values for the higher acceleration group in both concentric and eccentric phases. Conclusion: Distinct acceleration profiles affect the neuromuscular efficiency, force, and power during concentric and eccentric phases of isoinertial squatting exercise. To ensure immediate higher levels of power and force output without depriving the neuromuscular system, acceleration profiles higher than 2.5 m/s2 are preferable. The acceleration profiles could be an alternative to evolve the isoinertial exercise.

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Kyung-eun Lee, Seung-min Baik, Chung-hwi Yi, Oh-yun Kwon, and Heon-seock Cynn

Context: Side bridge exercises strengthen the hip, trunk, and abdominal muscles and challenge the trunk muscles without the high lumbar compression associated with trunk extension or curls. Previous research using electromyography (EMG) reports that performance of the side bridge exercise highly activates the gluteus medius (Gmed). However, to the best of our knowledge, no previous research has investigated EMG amplitude in the hip and trunk muscles during side bridge exercise in subjects with Gmed weakness. Objective: The purpose of this study was to examine the EMG activity of the hip and trunk muscles during 3 variations of the side bridge exercise (side bridge, side bridge with knee flexion, and side bridge with knee flexion and hip abduction of the top leg) in subjects with Gmed weakness. Design: Repeated-measures experimental design. Setting: Research laboratory. Patients: Thirty subjects (15 females and 15 males) with Gmed weakness participated in this study. Intervention: Each subject performed 3 variations of the side bridge exercise in random order. Main Outcome Measures: Surface EMG was used to measure the muscle activities of the rectus abdominis, external oblique, longissimus thoracis, multifidus, Gmed, gluteus maximus, and tensor fasciae latae (TFL), and Gmed/TFL muscle activity ratio during 3 variations of the side bridge exercise. Results: There were significant differences in Gmed (F2,56 = 110.054, P < .001), gluteus maximus (F2,56 = 36.416, P < .001), and TFL (F2,56 = 108.342, P < .001) muscles among the 3 side bridge exercises. There were significant differences in the Gmed/TFL muscle ratio (F2,56 = 20.738, P < .001). Conclusion: Among 3 side bridge exercises, the side bridge with knee flexion may be effective for the individuals with Gmed weakness among 3 side bridge exercises to strengthen the gluteal muscles, considering the difficulty of the exercise and relative contribution of Gmed and TFL.

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Bruno Augusto Lima Coelho, Helena Larissa das Neves Rodrigues, Gabriel Peixoto Leão Almeida, and Sílvia Maria Amado João

Context: Restriction in ankle dorsiflexion range of motion (ROM) has been previously associated with excessive dynamic knee valgus. This, in turn, has been correlated with knee pain in women with patellofemoral pain. Objectives: To investigate the immediate effect of 3 ankle mobilization techniques on dorsiflexion ROM, dynamic knee valgus, knee pain, and patient perceptions of improvement in women with patellofemoral pain and ankle dorsiflexion restriction. Design: Randomized controlled trial with 3 arms. Setting: Biomechanics laboratory. Participants: A total of 117 women with patellofemoral pain who display ankle dorsiflexion restriction were divided into 3 groups: ankle mobilization with anterior tibia glide (n = 39), ankle mobilization with posterior tibia glide (n = 39), and ankle mobilization with anterior and posterior tibia glide (n = 39). Intervention(s): The participants received a single session of ankle mobilization with movement technique. Main Outcome Measures: Dorsiflexion ROM (weight-bearing lunge test), dynamic knee valgus (frontal plane projection angle), knee pain (numeric pain rating scale), and patient perceptions of improvement (global perceived effect scale). The outcome measures were collected at the baseline, immediate postintervention (immediate reassessment), and 48 hours postintervention (48 h reassessment). Results: There were no significant differences between the 3 treatment groups regarding dorsiflexion ROM and patient perceptions of improvement. Compared with mobilization with anterior and posterior tibia glide, mobilization with anterior tibia glide promoted greater increase in dynamic knee valgus (P = .02) and greater knee pain reduction (P = .02) at immediate reassessment. Also compared with mobilization with anterior and posterior tibia glide, mobilization with posterior tibia glide promoted greater knee pain reduction (P < .01) at immediate reassessment. Conclusion: In our sample, the direction of the tibia glide in ankle mobilization accounted for significant changes only in dynamic knee valgus and knee pain in the immediate reassessment.

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Arthur Alves Dos Santos, James Sorce, Alexandra Schonning, and Grant Bevill

This study evaluated the performance of 6 commercially available hard hat designs—differentiated by shell design, number of suspension points, and suspension tightening system—in regard to their ability to attenuate accelerations during vertical impacts to the head. Tests were conducted with impactor materials of steel, wood, and lead shot (resembling commonly seen materials in a construction site), weighing 1.8 and 3.6 kg and dropped from 1.83 m onto a Hybrid III head/neck assembly. All hard hats appreciably reduced head acceleration to the unprotected condition. However, neither the addition of extra suspension points nor variations in suspension tightening mechanism appreciably influenced performance. Therefore, these results indicate that additional features available in current hard hat designs do not improve protective capacity as related to head acceleration metrics.

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Erika Zemková, Alena Cepková, and José M. Muyor

This study investigates postural responses to unexpected perturbations induced by a load release of different weights. Groups of 26 men (age 22.6 ± 2.4 years, height 178.0 ± 9.1 cm, and body mass 86.9 ± 11.5 kg) and 21 women (age 21.9 ± 2.7 years, height 168.8 ± 6.8 cm, and body mass 65.3 ± 8.7 kg) underwent load-triggered postural perturbations by 1 and 2 kg while standing on a force plate with either eyes open or eyes closed. Postural perturbations induced by a heavier load, representing about 2% and 3% of body weight in men and women, respectively, led to significantly higher peak anterior and peak posterior center of pressure displacements when compared with a lighter load (29.6% and 45.4%, respectively) both with eyes open (36.9%) and closed (42.1%). Their values were significantly lower in men than women only when a higher load was used (∼25%). However, there were no significant differences in time to peak anterior and posterior center of pressure displacements. These findings indicate that heavier load-induced postural perturbations are greater in women than men regardless of visual conditions. This underlines the importance of loading dose in the magnitude of postural responses to externally induced perturbations.

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W. Tolentino-Castro, L. Mochizuki, and H. Wagner

According to the literature, persons with intellectual disabilities have poor motor control in tasks in which motor anticipation is needed. Our study aimed to assess their motor behavior during interceptive tasks (a tennis ball interception with external-and-oneself throw conditions). A stick-bar was used as a reference or to support cloth to occlude a ball’s trajectory. Catch performance and interceptive behavior were analyzed (26 persons). The results show that high/low values of the initial approaching movement led to successful/successful catches, respectively. Our results are in line with the literature about the impact of poor motor control on performance in those with intellectual disabilities. We suggest that low anticipation may relate to problems in real-life situations.

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Chris M. Edwards

Clinical Scenerio: Neck pain is a costly symptom in both civilian and military worlds. While traditional treatments include deep neck flexor stabilizing exercises, manual therapy, electrical therapy, and other nonsurgical interventions, scapular orientation and stability training has emerged as a possible tool to reduce neck pain severity. Methods that can be coached at a distance could be of value in virtual appointments or circumstances where access to a qualified manual therapist is limited. Focused Clinical Question: What is the effectiveness of including exercise programs targeting scapular kinematics and stability to decrease neck pain? Summary of Key Findings: Exercise programs targeting scapular kinematics and stability, with coaching and individualized progressions, appear to reduce neck pain severity. Clinical Bottom Line: Evidence supports the inclusion of exercises for scapular kinematics and stability at a prescription of 3 sessions per week, with a duration of 4 or 6 weeks. Exercise programs should include a “learning” or coaching phase to ensure exercises are performed as intended, and exercise progressions should be based on participant ability rather than predetermined timelines. Further research is needed to better understand the benefits of this potential strategy and the statistical impact of scapular-focused exercise interventions on neck pain in specific populations like military and athletes. Strength of Recommendation: There is ‘Fair’ to ‘Good’ evidence from 2 level 1b single-blind randomized control studies and 1 level 2b pre-post test control design study supporting the inclusion of exercise programs targeting scapular kinematics and stability to decrease chronic neck pain severity.

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Rodrigo Rodrigues Gomes Costa, Jefferson Rodrigues Dorneles, Guilherme Henrique Lopes, José Irineu Gorla, and Frederico Ribeiro Neto

Context: Monitoring training loads and consequent fatigue responses are usually a result of personal trainers’ experiences and an adaptation of methods used in sports for people without disabilities. Currently, there is little scientific evidence on the relationship between training load and fatigue resulting from training sessions in wheelchair sports. Analogous to the vertical jump, which has been associated with competitive performance and used to assess fatigue in Olympic sports, the medicine ball throw (MBT) is a fast, feasible, and accessible test that might be used to measure performance outcomes in Paralympic athletes. Objective: To test the MBT responsiveness to detect meaningful changes after training sessions in beginner wheelchair basketball players (WBP). Design: Cross-sectional study. Setting: Rehabilitation Hospital Network, Paralympic Program. Participants: Twelve male WBP. Main Outcomes Measures: The participants performed 3 consecutive days of training sessions involving exercises of wheelchair basketball skills, strength, and power. The MBT test was performed pre and post training sessions. Results: The smallest worthwhile change for MBT was 0.10 cm, and the lower and upper limits were 3.54 and 3.75 m, respectively. On the first day, the MBT started below the smallest worthwhile change lower limit and increased above the upper limit (3.53 and 3.78 m, respectively). On the second day, the MBT pretraining and posttraining session results were near the sample mean (3.62 and 3.59 m, respectively). On the third day, the WBP started the MBT test training higher than the upper limit (3.78 m) and decreased to near the mean (3.58 m). Conclusions: During 3 consecutive days of training sessions, the magnitude-based inference model presented meaningful changes in MBT test performance. The accurate association of the magnitude-based inference model with the MBT allows coaches and sports team staff to interpret the correct magnitude of change in WBP performance.

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Guillermo Mendez-Rebolledo, Romina Figueroa-Ureta, Fernanda Moya-Mura, Eduardo Guzmán-Muñoz, Rodrigo Ramirez-Campillo, and Rhodri S. Lloyd

Context: Few reports have analyzed the effects of neuromuscular (NM) training programs on the injury incidence among youth female track-and-field athletes. Objective: To determine the effects of NM training on reducing lower limb injury incidence and to establish its effects on countermovement jump performance, balance, 30-m sprint, and joint position sense in youth female track-and-field athletes. Design: Single-blind, randomized controlled clinical trial. Setting:Sports research laboratory. Participants: Twenty-two female athletes were allocated into 2 groups: Conventional (CONV) training (n = 11; age = 15.3 [2.1] y) and NM training (n = 11; age = 15.0 [2.7] y). Interventions: Interventions were performed during the preseason of 6 weeks. The CONV training included anaerobic, strength, and aerobic training. The NM training consisted of a multicomponent program that integrated jumps, landings, and running with strength, endurance, agility, balance, and CORE training. Main Outcome Measures: A follow-up of the cohorts was carried out through the evaluation of lower limb injuries (main outcome) during a regular season (weeks 7–18). Secondary outcomes were measured before and after the intervention: Y-balance test, active joint repositioning, ground reaction force, and countermovement jump height. Results: The injury incidence rate was 17.89 injuries per 1000 hours athlete-exposure in CONV training, and 6.58 in NM training (relative risk = 0.38; 95% confidence interval,  0.18 to 0.82; P = .044). Particularly, the medial tibial stress syndrome incidence rate was 5.96 injuries per 1000 hours athlete-exposure in CONV training and 0.82 in NM training (relative risk = 0.17; 95% confidence interval, 0.02 to 1.12; P = .012). In addition, a significant training × time interaction was noted, favoring improvements in 30-m sprint and countermovement jump height after NM. Conclusion: The NM training may improve youth female athlete’s physical fitness and reduce their injury relative risk of medial tibial stress syndrome injury.