Abstract
BackgroundUnderstanding the root cause of the age-related impairment in muscle adaptive remodelling with resistance exercise training (RET) and developing pragmatic and accessible resistance exercise for older adults, are essential research directives.MethodsWe sought to determine whether indices of quadriceps muscle EMG activity in response to different modes of RET and activities of daily living (ADL), differed between 15 healthy younger (25 ± 3 years) and 15 older (70 ± 5 years) adults. On four separate days, participants completed a maximal voluntary contraction (MVC) of the knee extensors, followed by a 15 m walking task, stair climbing task (i.e. ADL) and lower-limb RET through body-weight squats (BW-RET) and seated knee extensions on a machine (MN-RET) or via elastic bands (EB-RET). Surface quadriceps electromyography (EMG) was measured throughout all tasks to provide indirect estimates of changes in muscle activity.ResultsMVC was significantly greater in young vs. older adults (Young: 256 ± 72 vs. Old: 137 ± 48 N·m, P < 0.001). EMG activity during all exercise tasks was significantly higher in older vs. younger adults when expressed relative to maximal EMG achieved during MVC (P < 0.01, for all). In addition, relative quadriceps muscle EMG activity was significantly greater in EB-RET (Young: 20.3 ± 8.7 vs. Old: 37.0 ± 10.7%) and MN-RET (Young: 22.9 ± 10.3, vs. Old: 37.8 ± 10.8%) compared with BW-RET (Young: 8.6 ± 2.9 vs. Old: 27.0 ± 9.3%), in young and older adults (P < 0.001). However, there was no significant difference in quadriceps EMG between EB-RET and MN-RET (P > 0.05).ConclusionsIn conclusion, relative quadriceps muscle EMG activity was higher across a range of activities/exercise modes in older vs. younger adults. The similar quadriceps muscle EMG activity between EB-RET and MN-RET provides a platform for detailed investigation of the neuromuscular and muscle metabolic responses to such pragmatic forms of RET to strengthen the evidence-base for this mode of RET as a potential countermeasure to sarcopenia.
Highlights
Ageing is associated with a precipitous loss of skeletal muscle strength, quantity/quality and functional capacity (Cruz-Jentoft et al, 2020; Rosenberg, 1997)
Quadriceps muscle EMG activity during Elastic resistance bands (EB)-resistance exercise training (RET) (Young: 20.3 ± 8.7% vs. Old: 37.0 ± 10.7%) and MN-RET (Young: 22.9 ± 10.3%, vs. Old: 37.8 ± 10.8%) were greater in older compared with younger adults (Table 2, Fig. 3, both P < 0.001, d > 1.40)
In agreement with our primary hypothesis, we demonstrated EB-RET to elicit comparable quadriceps muscle EMG activity to that of MN-RET in both younger and older adults when exercise volume and intensity was matched
Summary
Ageing is associated with a precipitous loss of skeletal muscle strength, quantity/quality and functional capacity (termed sarcopenia) (Cruz-Jentoft et al, 2020; Rosenberg, 1997). EMG activity during all exercise tasks was significantly higher in older vs younger adults when expressed relative to maximal EMG achieved during MVC (P < 0.01, for all). Relative quadriceps muscle EMG activity was significantly greater in EB-RET (Young: 20.3 ± 8.7 vs Old: 37.0 ± 10.7%) and MNRET (Young: 22.9 ± 10.3, vs Old: 37.8 ± 10.8%) compared with BW-RET (Young: 8.6 ± 2.9 vs Old: 27.0 ± 9.3%), in young and older adults (P < 0.001). Conclusions: In conclusion, relative quadriceps muscle EMG activity was higher across a range of activities/ exercise modes in older vs younger adults. The similar quadriceps muscle EMG activity between EB-RET and MN-RET provides a platform for detailed investigation of the neuromuscular and muscle metabolic responses to such pragmatic forms of RET to strengthen the evidence-base for this mode of RET as a potential countermeasure to sarcopenia
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
