Lower extremity general muscle moment patterns in healthy individuals during recumbent cycling

OBJECTIVE: The purpose of this study was to compare lower extremity generalized muscle moments across two workloads during recumbent bicycling in younger and older healthy adults. DESIGN: The study design was a comparative investigation of cycling patterns. BACKGROUND: Biomechanical data regarding muscle activation, kinematic, and kinetic patterns have been presented for upright cycling, but only a few studies have evaluated biomechanical patterns during the alternative configuration of recumbent cycling. METHODS: Twenty-four healthy adults, classified by age into two different groups, under 35 and over 50 years of age, rode a recumbent bicycle at a constant cadence (60-65 rpm) and at two different resistances (0.5 and 1.0 kg m) while kinematic and kinetic data were recorded. General muscle moments were calculated using joint kinematic and kinetic data via inverse dynamic equations. RESULTS: The ankle general muscle moment remained plantar flexor throughout the pedaling cycle; the knee general muscle moment remained flexor throughout the cycle, except during the power phase of the higher workload where an extensor general muscle moment was observed; and the hip general muscle moment was extensor with a transient flexor general muscle moment period during the recovery phase. Increased workload led to increases in ankle plantar flexor and knee extensor general muscle moment magnitudes, but no changes at the hip. Age had no effect on general muscle moment magnitudes or patterns. CONCLUSIONS: Configurational differences between the upright and recumbent bicycle do not affect patterns, but the total output requirements do affect the magnitudes of the general muscle moments. RELEVANCE: Based on previous studies, the recumbent bicycle appears to be a safe rehabilitation tool for post-cerebrovascular accident and cardiorespiratory patients, but in order to more properly and efficiently use the recumbent bicycle as a rehabilitation tool, normative biomechanical data are necessary. The current study is the first such investigation to report normative data of lower extremity general muscle moment patterns during recumbent cycling. Effects of age and workload were also demonstrated.