Hunter DeBusk

Preliminary Analysis of StrongArm® Ergoskeleton on Knee and Hip Kinematics and User Comfort

This study was constructed to assess the influence of wearing semi-soft exoskeletons on hip and knee kinematics when engaging in a box lifting task. Six healthy college aged students (age: 21.7 ± 2.3; gender: 4 males, 2 females; height: 177.0 ± 3.4 cm; weight: 77.1 ± 17.9 kg; hand dominance: all right) completed box lifting tasks (at 10% and 20% of their body weight) while wearing no exoskeleton and two exoskeleton designs. Lifting a box at 20% body weight increased perceived exertion and was associated with poor hip and knee kinematics in some conditions. Wearing the StrongArm® V22 ERGOSKELETON without hand cables may diminish some of the poor kinematics associated with lifting objects.

Influence of military-type workload and footwear on muscle exertion during static standing

Abstract Lower extremity muscular exertion and footwear design characteristics during a physiological workload have been shown to influence muscle activity. However, a dearth in the literature remains on muscular activation and exertion influenced by different military footwear when exposed to a military-type workload during static standing. The purpose of the study was to assess lower extremity muscular activity during erect standing, before (PRE) and after (POST) a military workload, in two military footwear [standard tactical (STD), minimalist (MIN)]. Twenty-two recreationally trained males (age: 22.1 § 2.1 years; height: 176.6 § 6.8 cm; mass: 79.8 § 9.7 kg) were tested, following a repeated measures counterbalanced footwear assignment. Participants performed maximal voluntary isometric contractions (MVICs) and bilateral static balance assessments before and after a 16-kg load-carrying treadmill workload. Electromyography (EMG) muscle activity was collected during the postural control tasks on ankle dorsiflexors, plantar flexors, inverters and everters in pre-workload and post-workload conditions. Dependent EMG variables of mean, peak, root-mean square, percent MVIC and co-contraction index were calculated and analyzed with a 2 £ 2 within-subjects repeated measures analysis of variance with the alpha level set p < 0.05. Pre-workload muscle activity did not differ between footwear. However, MIN demonstrated lower muscle activity during post-workload static standing. Additionally, a shorter workload time was recorded while donning STD compared to MIN. In acute conditions, lower extremity muscle activity does not differ between the military footwear. However, after undergoing an occupation-related workload, standard tactical footwear increases muscle exertion, thus suggesting a diminished effect on lower extremity muscle activity.