Hillary H. Holmes, Randall T. Fawcett, and Jaimie A. Roper
Walking is an integral indicator of human health commonly investigated while walking overground and with the use of a treadmill. Unlike fixed-speed treadmills, overground walking is dependent on the preferred walking speed under the individuals’ control. Thus, user-driven treadmills may have the ability to better simulate the characteristics of overground walking. This pilot study is the first investigation to compare a user-driven treadmill, a fixed-speed treadmill, and overground walking to understand differences in variability and mean spatiotemporal measures across walking environments. Participants walked fastest overground compared to both fixed and user-driven treadmill conditions. However, gait cycle speed variability in the fixed-speed treadmill condition was significantly lower than the user-driven and overground conditions, with no significant differences present between overground and user-driven treadmill walking. The lack of differences in variability between the user-driven treadmill and overground walking may indicate that the user-driven treadmill can better simulate the variability of overground walking, potentially leading to more natural adaptation and motor control patterns of walking.
Lauren E. Schroeder, Rachel L. Tatarski, and Joshua T. Weinhandl
Decreased dorsiflexion range of motion (DROM) can be modified using static stretching and joint mobilizations and may attenuate known knee anterior cruciate ligament injury risk factors. It is not known how these interventions compare to each other and how they improve knee landing mechanics. This study’s purpose was to determine the immediate effects of static stretching and joint mobilization interventions on DROM measurement changes and right-leg drop jump knee landing mechanics. Eighteen females and 7 males, all recreationally active, completed 2 study sessions. Active and passive DROM, the weight-bearing lunge test, the anterior reach portion of the Star Excursion Balance Test, and a right-leg drop jump landing task were completed before and after the intervention. Change in DROM (ΔDROM) was calculated for DROM assessments between preintervention and postintervention. Pairwise dependent t tests determined no differences in ΔDROM between interventions, and statistical parametric mapping determined increased knee flexion (P = .004) and decreased anterior shear force (P = .015) during landing after both interventions. Increased DROM improves sagittal plane displacement and loading at the knee. Stretching may be a more feasible option in a healthy population for those wanting to maintain range of motion and decrease knee injury risk without physical therapist involvement.
Ahalee C. Farrow and Ty B. Palmer
This study aimed to examine the effects of age on hip flexion maximal and rapid strength and rectus femoris (RF) muscle size and composition in men. Fifteen young (25  y) and 15 older (73  y) men performed isometric hip flexion contractions to examine peak torque and absolute and normalized rate of torque development (RTD) at time intervals of 0 to 100 and 100 to 200 milliseconds. Ultrasonography was used to examine RF muscle cross-sectional area and echo intensity. Peak torque, absolute RTD at 0 to 100 milliseconds, and absolute and normalized RTD at 100 to 200 milliseconds were significantly lower (P = .004–.045) in the old compared with the young men. The older men exhibited lower cross-sectional area (P = .015) and higher echo intensity (P = .007) than the young men. Moreover, there were positive relationships between cross-sectional area and absolute RTD at 0 to 100 milliseconds (r = .400) and absolute RTD at 100 to 200 milliseconds (r = .450) and negative relationships between echo intensity and absolute RTD at 100 to 200 milliseconds (r = −.457) and normalized RTD at 100 to 200 milliseconds (r = −.373). These findings indicate that hip flexion maximal and rapid strength and RF muscle size and composition decrease in old age. The relationships observed between ultrasound-derived RF parameters and measurements of RTD suggest that these age-related declines in muscle size and composition may be relevant to hip flexion rapid torque production.
Georde Vuillermin, Kelly-Ann Bowles, Ross Iles, and Cylie Williams
Health professionals responsible for return to work plans have little data about allied health movement to guide recommendations following lower back injury. This study aimed to quantify the lumbar movement patterns of allied health professionals within a health care facility throughout a normal workday. An observational case study was undertaken at a public health care facility with 122 allied health professionals. The lumbar movements were recorded with the ViMove together with pain scale measurement. The mean (SD) recording time for allied health was 7.7 (0.7) hours. A mean (SD) 3 (1.4) hours total were spent in standing, 3.8 (1.7) hours in sitting, and 0.8 (0.4) hours in locomotion. Forty-nine flexions were recorded on average per session, most identified as short term (<30 s) within low range (0°–20°). Lumbar movement patterns differed among professions. Thirty-seven (31%) participants reported a history of lower back injury, and 57 (47%) reported low back pain at the end of their workday. This study provides an insight into allied health professionals’ back movement in a hospital or community-based health care setting. These data may inform those who make return to work recommendations or provide rehabilitation services for allied health professionals working with a lower back injury.
Thomas J. Sherriff, Kyle T. Ebersole, and David J. Cornell
Restricted gastrocnemius length may impair movement efficiency during functional movements. However, this is yet to be examined among tactical athletes. This study examined the relationship between gastrocnemius muscle length and movement compensations during a two-leg overhead squat among career firefighters. Bilateral ankle dorsiflexion passive range of motion data were collected from 50 firefighters, and movement compensations observed during a two-leg overhead squat were recorded. Firefighters with reduced average ankle dorsiflexion passive range of motion were more likely to demonstrate movement compensations during the overhead squat. Clinicians should utilize interventions that lengthen gastrocnemius musculature to improve the squat movement efficiency of firefighters.
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.
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.