This study examined the prevalence of protective stepping and accompanying preparatory postural responses associated with lateral weight transfer (WT) while subjects attempted to sustain stationary standing. The subjects were 92 healthy young and older adults and persons with vestibular hypo-function. Force platform and whole-body-motion recordings were used to evaluate the prevalence of stepping and WT responses during stationary standing (eyes open or closed) using a semi-tandem foot position. WT components were also evaluated for volitionally requested step initiation, and as a function of support base configuration and direction of stepping among younger subjects. Only 10% of trials by subjects with bilateral vestibular hypofunction (BVH) during semi-tandem standing with eyes closed were completed without a step, while 31% of subjects with UVH, 69% of healthy elders, and all young healthy subjects were able to stand for the entire 7-sec trials. WT responses always preceded volitional steps from a standard feet-parallel orientation but occurred in only 13% of the spontaneous steps. The prevalence of WT was influenced by the direction of volitional stepping from semi-tandem standing, but not by the initial standing width. Spontaneous stepping to maintain standing balance is a naturally occurring and prevalent behavior among older adults and persons with vestibular hypo-function during tests of quasi-static standing. Differences between volitional and spontaneous step initiation involving the prevalence of preparatory lateral WT are a complex function of motor planning, mechanical constraints, and functional context.
David E. Krebs, Peter H. Velyvis and Mark W. Rogers
Tyler A. Beauregard, Jade Vaile, Lucas Whitney, Mark Merrick and Valerie Moody
Context: Athletes in combat sports who have sustained facial hematomas during competition have traditionally been treated with an enswell. These treatments take place between rounds of the competition and generally last less than 60 seconds. The efficacy of this modality has not been studied. Other modalities may provide a more effective cryotherapy treatment in this timeframe. Objective: To compare the efficacy of different forms of rapid cryotherapy to cause surface temperature changes of the face within 60 seconds of application. Design: Crossover study. Setting: Laboratory. Participants: Eleven healthy men (age 21.73 [1.42] y, mass 82.1 [5.6] kg, height 177.2 [7.0] cm). Interventions: A 60-second treatment using chilled surgical steel enswell, copper, commercial cold pack, aluminum, brass, ice cube, ice pack, and saltwater pack. Main Outcome Measures: Preintervention and postintervention surface facial temperatures. Results: The ice bag, cold pack, ice cube, saltwater pack, and stainless-steel enswell caused statistically different temperatures preintervention to postintervention. The ice bag and saltwater pack cause statistically greater cooling than the other materials tested. Conclusions: This study does not support the clinical use of an enswell to provide short-duration cryotherapy treatments to facial tissue, as ice packs are more effective.
D. Clark Dickin, Emily Johann, He Wang and Jennifer K. Popp
Drop height and fatigue have been shown in isolation to affect landing mechanics and increase the risk of sustaining an anterior cruciate ligament injury. The purpose of this study was to identify the combined effects of drop height and fatigue on landing mechanics in recreationally active females. To assess this, 11 healthy, young adult females performed a series of drop jumps from randomized heights before and following a lower extremity fatiguing protocol. Findings for kinematic results demonstrated that hip flexion decreased at initial contact (P = .003) and maximum hip (P = .005) and knee flexion (P = .001) angles increased with increases in drop height. Kinetic results demonstrated that vertical ground reaction forces and joint moments and powers increased as height increased. Ground reaction forces and maximum knee valgus increased from pre- to postfatigue with interactive effects observed in frontal plane hip angle at impact and peak ankle moment. These results confirm the effects of drop height and fatigue and highlighted interactions between these factors. The differential effect of fatigue as a function of drop heights helps to illustrate potentially risky situations that should be addressed in training and injury prevention programs.
Robert J. Delmore, Kevin G. Laudner and Michael R. Torry
Hip-adductor strains are among the most common lower-extremity injuries sustained in athletics. Treatment of these injuries involves a variety of exercises used to target the hip adductors.
To identify the varying activation levels of the adductor longus during common hip-adductor exercises.
24 physically active, college-age students.
Main Measurement Outcomes:
Peak and average electromyographic (EMG) activity of the adductor longus muscle during the following 6 hip-adductor rehabilitation exercises: side-lying hip adduction, ball squeezes, rotational squats, sumo squats, standing hip adduction on a Swiss ball, and side lunges.
The side-lying hip-adduction exercise produced more peak and average activation than any other exercise (P < .001). Ball squeezes produced more peak and average activation than rotational squats, sumo squats, and standing adduction on a Swiss ball (P < .001). Ball squeezes had more average activation than side lunges (P = .001). All other variables for peak activation during the exercises were not statistically significant (P > .08). These results allowed the authors to provide an overall ranking system (highest to lowest muscle activation): side-lying hip adduction, ball squeezes, side lunges, standing adduction on a Swiss ball, rotational squats, and sumo squats.
The study provides a ranking system on the activation levels of the adductor longus muscle for 6 common hip-adductor rehabilitation exercises, with the side-lying hip-adduction and ball-squeeze exercises displaying the highest overall activation.
Gregory M. Gutierrez, Nicole D. Jackson, Kristin A. Dorr, Sarah E. Margiotta and Thomas W. Kaminski
Lateral ankle sprains occur more frequently than any other orthopedic injury. Athletes often report sustaining more injuries late in competition when fatigue is present.
To evaluate neuromuscular function of the ankle musculature after fatigue. Design: Experimental, pretest-posttest.
Ten female and 9 male college-aged subjects.
Fatigue was induced via continuous concentric and eccentric muscle actions of the ankle: inversion (INV), eversion (EV), plantar flexion (PF), and dorsiflexion (DF).
Main Outcome Measures:
Peak torque (PT), peak EMG, and median frequency (MF) were calculated prefatigue and postfatigue in the tibialis anterior (TA), peroneus longus (PER), and lateral gastrocnemius (GAS) muscles.
Main effects were noted for test (P < 0.0125) in all statistical tests performed indicating changes in PT, peak EMG, and MF after fatigue.
A significant decrease in MF of the PER muscle after PF fatigue and corresponding with a decreased firing rate, may be of importance, especially with regard to the role in countering the violent moment seen with inversion ankle sprains.
Leo Ng, Amity Campbell, Angus Burnett, Anne Smith and Peter O’Sullivan
There is a high prevalence of low back pain (LBP) in adolescent male rowers. In this study, regional lumbar spinal kinematics and self-reported LBP intensity were compared between 10 adolescent rowers with moderate levels of LBP relating to rowing with 10 reporting no history of LBP during a 15-minute ergometer trial using an electromagnetic tracking system. Adolescent male rowers with LBP reported increasing pain intensity during ergometer rowing. No significant differences were detected in mean upper or lower lumbar angles between rowers with and without LBP. However, compared with rowers without pain, rowers with pain: (1) had relatively less excursion of the upper lumbar spine into extension over the drive phase, (2) had relatively less excursion of the lower lumbar spine into extension over time, (3) had greater variability in upper and lower lumbar angles over the 15-minute ergometer trial, (4) positioned their upper lumbar spine closer to end range flexion for a greater proportion of the drive phase, and (5) showed increased time in sustained flexion loading in the upper lumbar spine. Differences in regional lumbar kinematics exist between adolescent male rowers with and without LBP, which may have injury implication and intervention strategies.
Annina B. Schmid, Linda Dyer, Thomas Böni, Ulrike Held and Florian Brunner
Various studies report decreased muscle activation in the concavity of the curve in patients with scoliosis. Such decreased muscle-performance capacity could lead to sustained postural deficits.
To investigate whether specific asymmetrical sports therapy exercises rather than symmetrical back strengthening can increase EMG amplitudes of paraspinal muscles in the concavity of the curve.
16 patients with idiopathic scoliosis.
Patients performed 4 back-strengthening exercises (front press, lat pull-down, roman chair, bent-over barbell row) during 1 test session. Each exercise was performed in a symmetrical and asymmetrical variant and repeated 3 times.
Main Outcome Measure:
EMG amplitudes of the paraspinal muscles were recorded in the thoracic and lumbar apexes of the scoliotic curve during each exercise. Ratios of convex- to concave-side EMG activity were calculated.
Statistical analysis revealed that the asymmetrical variants of front press at the lumbar level (P = .002) and roman chair and bent-over barbell row at the thoracic level (P < .0001, .001 respectively) were superior in increasing EMG amplitudes in the concavity of the scoliotic curve.
Specific asymmetrical exercises increase EMG amplitudes of paraspinal muscles in the concavity. If confirmed in longitudinal studies measuring improvements of postural deficits, these exercises may advance care of patients with scoliosis.
Harpa Helgadottir, Eythor Kristjansson, Sarah Mottram, Andrew Karduna and Halldor Jonsson Jr.
Clinical theory suggests that altered alignment of the shoulder girdle has the potential to create or sustain symptomatic mechanical dysfunction in the cervical and thoracic spine. The alignment of the shoulder girdle is described by two clavicle rotations, i.e, elevation and retraction, and by three scapular rotations, i.e., upward rotation, internal rotation, and anterior tilt. Elevation and retraction have until now been assessed only in patients with neck pain. The aim of the study was to determine whether there is a pattern of altered alignment of the shoulder girdle and the cervical and thoracic spine in patients with neck pain. A three-dimensional device measured clavicle and scapular orientation, and cervical and thoracic alignment in patients with insidious onset neck pain (IONP) and whiplash-associated disorder (WAD). An asymptomatic control group was selected for baseline measurements. The symptomatic groups revealed a significantly reduced clavicle retraction and scapular upward rotation as well as decreased cranial angle. A difference was found between the symptomatic groups on the left side, whereas the WAD group revealed an increased scapular anterior tilt and the IONP group a decreased clavicle elevation. These changes may be an important mechanism for maintenance and recurrence or exacerbation of symptoms in patients with neck pain.
Alison B. Pritchard Orr, Kathy Keiver, Chris P. Bertram and Sterling Clarren
Test (CCTT). Successful performance on the CCTT requires utilization of a variety of EF skills, such as sustained attention, perceptual tracking, sequencing, psychomotor speed, and cognitive flexibility ( Llorente et al., 2003 ). Thus, the CCTT provides a measure of overall EF ability rather than a
Donna L. Goodwin and Amanda Ebert
may be actively disavowed; Scully, 2010 ). Ableism, as a network of beliefs and practices, constructs bodies as impaired and the Other who is different, undesirable, and in need of repair or modification ( Campbell, 2001 , 2008 , 2009 ; Hodge & Runswick-Cole, 2013 ). It creates and sustains