Abstract
The purpose of this study was to investigate the effects of how limb dominance and joint immobilization alter markers of physical demand and muscle activation during ambulation with axillary crutches. In a crossover, counterbalanced study design, physically active females completed ambulation trials with three conditions: (1) bipedal walking (BW), (2) axillary crutch ambulation with their dominant limb (DOM), and (3) axillary crutch ambulation with their nondominant limb (NDOM). During the axillary crutch ambulation conditions, the non-weight-bearing knee joint was immobilized at a 30-degree flexion angle with a postoperative knee stabilizer. For each trial/condition, participants ambulated at 0.6, 0.8, and 1.0 mph for five minutes at each speed. Heart rate (HR) and rate of perceived exertion (RPE) were monitored throughout. Surface electromyography (sEMG) was used to record muscle activation of the medial gastrocnemius (MG), soleus (SOL), and tibialis anterior (TA) unilaterally on the weight-bearing limb. Biceps brachii (BB) and triceps brachii (TB) sEMG were measured bilaterally. sEMG signals for each immobilization condition were normalized to corresponding values for BW.HR (p < 0.001) and RPE (p < 0.001) were significantly higher for both the DOM and NDOM conditions compared to BW but no differences existed between the DOM and NDOM conditions (p > 0.05). No differences in lower limb muscle activation were noted for any muscles between the DOM and NDOM conditions (p > 0.05). Regardless of condition, BB activation ipsilateral to the ambulating limb was significantly lower during 0.6 mph (p = 0.005) and 0.8 mph (p = 0.016) compared to the same speeds for BB on the contralateral side. Contralateral TB activation was significantly higher during 0.6 mph compared to 0.8 mph (p = 0.009) and 1.0 mph (p = 0.029) irrespective of condition. In conclusion, limb dominance appears to not alter lower limb muscle activation and walking intensity while using axillary crutches. However, upper limb muscle activation was asymmetrical during axillary crutch use and largely dependent on speed. These results suggest that functional asymmetry may exist in upper limbs but not lower limbs during assistive device supported ambulation.
Highlights
A multitude of evidence has substantiated findings of asymmetrical muscle activation during able-bodied bipedal walking (BW), which may lead to inter-limb variability of metabolic demands [5,6]. It is currently unknown if functional limb asymmetry exists with the use of assistive devices (AD) during ambulation, which may have important implications for individuals recovering from an injury, undergoing rehabilitation, or with a chronic condition
The use of ADs for ambulation is common and has been shown to increase both cardiovascular and metabolic strain compared to BW [4,26,29]
While functional limb asymmetry between dominant and nondominant limbs has been documented during unassisted BW [6,12], no investigations to date have studied whether limb asymmetry exists with AD use and unilateral limb immobilization
Summary
While necessary to maintain mobility either acutely or chronically, the use of ADs imposes higher metabolic demand and cardiorespiratory stress during ambulation versus able-bodied bipedal walking (BW) [4]. A multitude of evidence has substantiated findings of asymmetrical muscle activation during able-bodied BW, which may lead to inter-limb variability of metabolic demands [5,6]. It is currently unknown if functional limb asymmetry exists with the use of ADs during ambulation, which may have important implications for individuals recovering from an injury, undergoing rehabilitation, or with a chronic condition
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
