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 (F 2,56 = 110.054, P < .001), gluteus maximus (F 2,56 = 36.416, P < .001), and TFL (F 2,56 = 108.342, P < .001) muscles among the 3 side bridge exercises. There were significant differences in the Gmed/TFL muscle ratio (F 2,56 = 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.
Andrea Stracciolini, Caitlin M. McCracken, William P. Meehan III, and Matthew D. Milewski
Purpose: To study mental health, sleep duration, and daytime sleepiness in young athletes. Methods: A cross-sectional questionnaire study was conducted. The main outcome measures included sleep duration and daytime sleepiness. Results: Study participants included 756 athletes with a mean age of 13.5 years. A total of 39% (n = 296/756) reported not meeting current sleep recommendations for age. Athletes >12 years and with a self-reported anxiety and/or depression history were less likely to meet sleep recommendations and showed higher daytime sleepiness (adjusted odds ratio [aOR] = 1.29, 95% confidence interval [CI] [1.2, 1.4], β [SE] = 3.06 [0.74], respectively). Athletes with goal-oriented reasons for playing versus enjoyment (52% vs. 35%, aOR = 1.70, 95% CI [1.12, 2.58]) were less likely to meet sleep recommendations. Night time internet access and weeknight homework hours were negatively associated with sleep recommendations (aOR = 1.68, 95% CI [1.68, 2.47] and aOR = 3.11, 95% CI [1.82, 5.3]) and positively associated with daytime sleepiness (β [SE] = 1.44 [0.45] and 2.28 [0.59]). Conclusions: Many young athletes are not meeting sleep recommendations. Associated factors include mental health, reasons for play, internet access, and homework demand.
Jihong Park, Kyeongtak Song, and Sae Yong Lee
Context: It is unclear if lower-extremity joint cooling alters biomechanics during a functional movement. Objective: To investigate the effects of unilateral lower-extremity cryotherapy on movement alterations during a single-leg drop jump. Design: A crossover design. Setting: Laboratory. Patients: Twenty healthy subjects (10 males and 10 females; 23 y, 169 cm, 66 kg). Intervention(s): Subjects completed a single-leg drop jump before and after a 20-minute ankle or knee joint cooling on the right leg, or control (seated without cooling) on 3 separate days. Main Outcome Measures: Time to peak knee flexion, vertical ground reaction force, lower-extremity joint angular velocity (sagittal plane only), and angle and moment (sagittal and frontal planes) in the involved leg over the entire ground contact (GC; from initial contact to jump-off) during the first landing. Time to peak knee flexion was compared using an analysis of variance; the rest of the outcome measures were analyzed using functional analyses of variance (P < .05). Results: Neither joint cooling condition changed the time to peak knee flexion (F 2,95 = 0.73, P = .49). Ankle joint cooling reduced vertical ground reaction force (55 N at 4% of GC), knee joint angular velocity (44°/s during 5%–9% of GC), and knee varus moment (181 N·m during 18%–20% of GC). Knee joint cooling resulted in a reduction in knee joint angular velocity (24°/s during 37%–40% of GC) and hip adduction moment (151 N·m during 46%–48% of GC), and an increase in hip joint angular velocity (16°/s during 49%–53% of GC) and plantarflexion angle (1.5° during 11%–29% of GC). Conclusion: Resuming activity immediately after lower-extremity joint cooling does not seem to predispose an individual to injury during landing because altered mechanics are neither overlapping with the injury time period nor of sufficient magnitude to lead to an injury.
Justin L. Rush, David A. Sherman, David M. Bazett-Jones, Christopher D. Ingersoll, and Grant E. Norte
Context: Arthrogenic muscle inhibition (AMI) is a common neurophysiological response to joint injury. While athletic trainers (ATs) are constantly treating patients with AMI, it is unclear how clinicians are using the available evidence to treat the condition. Objective: To investigate ATs’ general knowledge, clinical practice, and barriers for treating AMI. Methods: A cross-sectional web-based survey was utilized. The survey was distributed to a random sample of 3000 ATs from the National Athletic Trainers’ Association and through social media. 143 board certified ATs (age: 34.6 [10.3] y; experience: 11.7 [9.8] y) from various clinical settings and educational backgrounds were included in the analysis. Results: One hundred one respondents were able to correctly identify the definition of AMI. The majority of these respondents correctly reported that joint effusion (n = 95, 94.1%) and abnormal activity from joint receptors (n = 91, 90.1%) resulted in AMI. Of the 101 respondents, only 58 (57.4%) reported using disinhibitory interventions to treat AMI. The most frequently used evidence supported interventions were transcutaneous electrical nerve stimulation (n = 38, 65.5%), neuromuscular electrical stimulation (n = 33, 56.9%), and focal joint cooling (n = 25, 43.1%). The interventions used correctly most often based on current evidence were neuromuscular electrical stimulation (n = 29/33, 87.9%) and transcutaneous electrical nerve stimulation (n = 26/38, 68.4%). Overall, difficulty quantifying AMI (n = 62, 61.24%) and lack of education (n = 71, 76.2%) were most frequently perceived as barriers. Respondents that did not use disinhibitory interventions perceived lack of experience treating AMI, understanding the terminology, and access to therapeutic modalities more often than the respondents that reported using disinhibitory interventions. Conclusion: Further education about concepts and treatment about AMI is warranted for ATs. Continued understanding of ATs’ clinical practice in regard to AMI may help identify gaps in athletic training clinical education.
Meaghan Hindle, Katherine Aldinger, and Geoff Dover
Context: Chronic pain is a challenge for Athletic Trainers and Athletic Therapists working in a clinical or university setting. The fear avoidance model, including catastrophizing, is well established in other health professions but is not established in Athletic Training and Athletic Therapy and may affect rehabilitation outcomes. Objective: To measure the influence of catastrophizing on rehabilitation outcomes of patients being treated in an Athletic Therapy setting. Design: Prospective single group pre–post design. Setting: Student Athletic Therapy clinic. Patients: A total of 92 patients were evaluated at initial assessment, and 49 were evaluated at follow-up. Intervention: All participants completed self-reported function questionnaires to assess level of injury and then received individualized treatments for a variety of musculoskeletal injuries. All measures were completed at initial assessment and at follow-up approximately 6 weeks later. Main Outcome Measures: The authors measured function using a variety of patient self-reported functional questionnaires: the Disability of the Arm, Shoulder, and Hand; Lower Extremity Functional Scale; the Neck Disability Index; and the Oswestry Disability Index depending on injury site. Catastrophizing was measured using the Pain Catastrophizing Scale. Results: Function significantly improved from the initial assessment to the follow-up (P > .001). Patients with acute pain experienced a significantly greater improvement in function between the initial assessment and follow-up compared with participants with chronic pain (P = .050). Those with high catastrophizing presented with lower levels of function at initial assessment (66.8%) and follow-up (72.1%) compared with those with low catastrophizing (80.8% and 87.0%, respectively). Conclusion: Similar to other studies in other professions, the function of patients with chronic pain does not improve as much compared with patients recovering from acute pain in an Athletic Therapy setting. It is important to measure patient-reported outcomes to evaluate patient rehabilitation progress. Rehabilitating patients with chronic pain is a challenge, and pain catastrophizing should be evaluated at the initial assessment since catastrophizing is associated with worse function.
Ghazala T. Saleem, Beth S. Slomine, and Stacy J. Suskauer
Context: Objective and expedient assessments of standing postural control incorporating static and dynamic tasks are necessary for identifying subtle motor deficits and clearing children to return to high-risk activities after concussion. The Revised Physical and Neurological Examination for Subtle Signs (PANESS) gaits and stations tasks evaluate both static and dynamic aspects of postural control. While the PANESS gaits and stations subscale is sensitive to concussion in youth, the benefit of each specific task for this purpose is unknown. Purpose: This study evaluated whether specific PANESS tasks identify postural impairments after youth concussion. Design: Cross-sectional study. Setting: Academicallyaffiliated research laboratory. Participants: Sixty youth, ages 10–17 years, comprised 3 groups: (1) youth symptomatic from concussion (4–14 d postinjury [n = 18]), (2) clinically-recovered youth (27–122 d postinjury [n = 15]), and (3) age- and gender-matched never-concussed controls (n = 27). Main Outcome Measure: PANESS gaits and stations tasks (6 dynamic and 3 static) at the time of the initial research visit. Results: Kruskal–Wallis statistic identified a significant main effect of group on standing on one foot (a 30-s task). Both symptomatic and clinically-recovered youth showed deficits on standing on one foot relative to controls. Conclusions: Single-leg tasks of longer duration may maximize the ability to detect residual postural deficits after concussion and can be readily incorporated in targeted sport rehabilitation protocols.