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.
Denys Batista Campos, Isabella Christina Ferreira, Matheus Almeida Souza, Macquiden Amorim Jr, Leonardo Intelangelo, Gabriela Silveira-Nunes, and Alexandre Carvalho Barbosa
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.
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.
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.
Samuel C. Fischer, Darren Q. Calley, and John H. Hollman
Clinical Scenario : Low back pain is a common condition for the general population with 29% of adults having low back pain within the last 3 months. A deadlift is described as a free weight exercise in which a barbell is lifted from the floor in a continuous motion by extending the knees and hips. For those without low back pain, the deadlift was found to have the highest muscle activation of paraspinal musculature compared with other exercises. There are a limited number of studies that investigate the usefulness of incorporating deadlifts as part of a rehabilitation program for low back pain. Clinical Question: For those who live with low back pain, is an exercise routine that includes a deadlift a viable treatment option to improve pain and/or function? Summary of Key Findings: The literature search yielded 3 total studies meeting the inclusion and exclusion criteria: 1 randomized control trial, 1 secondary analysis of a randomized control trial, and 1 cohort study. Exercise programs that include deadlifts can yield improvements in both pain and function for those living with low back pain but were not found to be more beneficial than low load motor control exercises. Those with lower pain levels and higher baseline lumbar extension strength may be most appropriate to participate in an exercise program that includes deadlifts. Further research is needed to compare exercise programs that include deadlifts to other interventions for those living with low back pain. Clinical Bottom Line: There is minimal evidence that exercise programs that included deadlifts are a clinically effective option for the treatment of low back pain for both pain scores and functional outcome measures. Strength of Recommendation: Level B evidence exists that exercise programs that include deadlifts are a clinically effective option for the treatment of low back pain for both pain scores and functional outcome measures.
Scott Benson Street, Matthew Rawlins, and Jason Miller
Clinical Scenario: Ankle fractures are a frequent occurrence, and they carry the potential for syndesmosis injury. The syndesmosis is important to the structural integrity of the ankle joint by maintaining the proximity of the tibia, fibula, and talus. Presently, the gold standard for treating an ankle syndesmosis injury is to insert a metallic screw through the fibula and into the tibia. This technique requires a second intervention to remove the hardware, but also carries an inherent risk of breaking the screw during rehabilitation. Another fixation technique, the Tightrope™, has gained popularity in treating ankle syndesmosis injuries. The TightRope™ involves inserting Fiberwire® through the tibia and fibula, which allows for stabilization of the ankle mortise and normal range of motion. Clinical Question: In patients suffering from ankle syndesmosis injuries, is the Tightrope™ ankle syndesmosis fixation system more effective than conventional screw fixation at improving return to work, pain, and patient-reported outcome measures? Summary of Key Findings: Five studies were selected to be critically appraised. The PEDro checklist was used to score 2 randomized control trials, and the Downs & Black checklist was used to score the cohort study on methodology and consistency. Two systematic reviews were also appraised. All 5 articles demonstrated support for using the TightRope™ fixation. Clinical Bottom Line: There is moderate evidence to support the use of the TightRope™ syndesmosis fixation system, as it provides both clinician- and patient-reported outcomes that are similar to those using the conventional metallic screw, with a shortened time to recover and return to activity. Strength of Recommendation: Grade A evidence exists in support of using the TightRope™ fixation system in place of the metallic screw following ankle syndesmosis injury.
Tomoko Aoki and Koji Kadota
The present study examined the effects of daily activities of the hands on finger motor function in older adults. Maximum tapping frequency with each finger during single-finger tapping and alternate movements of index–middle, middle–ring, and ring–little finger pairs during double-finger tapping were compared between older adults who used their hands actively in their daily lives and those who did not. The active participants had significantly faster tapping rates for the ring finger in the single-finger tapping and the middle–ring finger pair in the double-finger tapping than did the inactive participants. Thus, daily activity of the hands in older adults could be effective at preventing the loss of dynamic motor function in individual fingers, especially with greater difficulty in movement, resulting from the degeneration with age.
Alexandre Nehring, Thiago Teixeira Serafim, Elisa Raulino Silva, Fábio Sprada de Menezes, Nicola Maffulli, Luciana Sayuri Sanada, and Rodrigo Okubo
Context: Myofascial self-release is performed using a roller to exert pressure on the soft tissues and to promote effects similar to those of traditional massage. However, there is no standardization regarding its application, mainly in relation to time. Objective: To evaluate the effects of myofascial self-release with a rigid roller on range of motion (ROM), pressure pain threshold (PPT), and hamstring strength in asymptomatic individuals following 2 different times of intervention. Design: Randomized, controlled, blind, clinical trial comparing preintervention and immediately postintervention within 2 groups. Setting: Institutional physiotherapy clinic. Participants: A total of 40 university students (18–30 y), who had no symptoms, participated. Intervention: Foam roller for 30 seconds and 2 minutes for group 2. Main Outcome Measures: Hamstring PPT, knee-extension ROM, and peak knee-flexion torque measured before and immediately after the intervention. Results: Both groups experienced a statistically significant increase in ROM compared with baseline (30 s and 2 min for group 2 P < .024). There were no statistically significant differences comparing peak knee-flexion torque or PPT. Conclusions: Hamstring myofascial self-release using a roller for 30 seconds or 2 minutes produced an increase in ROM in healthy individuals. PPT and peak knee-flexion isometric torque showed no effects.