Functional Relevance of Relative Maintenance of Maximal Eccentric Quadriceps Torque in Healthy Old Adults

Abstract

Background: Old referenced to young adults show a relative maintenance of maximal eccentric (RELM) compared to concentric muscle torque: ∼76 and ∼59%, respectively. However, it is unknown if RELM affords functional benefits in old adults. Objective: We examined if there is specificity between the two types of peak quadriceps torque (i.e., concentric and eccentric) and timed gait performance measured during level, ramp, and stair walking and if gait performance was higher in old adults with high versus low RELM. Methods: We measured peak concentric and eccentric quadriceps torque at 60 and 120°/s and timed gait at habitual and safe-fast speeds in healthy young (age 22.7 years, n = 24) and old (age 70.0 years, n = 21) adults. Results: Comparable to previous studies, RELM was 21%, but instead of the anticipated specificity, we found that concentric compared with eccentric torque was more strongly associated with gait performance than eccentric torque, independently of walking direction and age (R² = 0.16: eccentric vs. descending gaits; R² = 0.17: eccentric vs. ascending gaits; R² = 0.45: concentric vs. descending gaits; R² = 0.56: concentric vs. ascending gaits, n = 45, all p < 0.01). Furthermore, old adults (n = 10) with ∼30% greater than normal levels of RELM (n = 11) ambulated at similar velocities measured on level and inclined surfaces. Conclusion: Normal and 30% above normal levels of RELM do not seem to increase or predict healthy old adults' gait performance on level and inclined surfaces. Future work should examine if RELM is associated with a heightened performance in other measures of neuromuscular function, such as gait biomechanics, muscle activation, as well as rate and control of voluntary force development in old adults with high or low mobility.

Advanced Age Redistributes Positive but Not Negative Leg Joint Work during Walking

“…In partial agreement with previous studies, we observed a relative maintenance of maximal voluntary eccentric versus concentric muscle function for the knee extensors ( 23 , 26 ) but not the plantarflexors ( 24 ). Porter et al ( 24 ) also observed relative eccentric strength maintenance for the plantarflexors, but their sample included females only and older females tend to show a greater eccentric strength maintenance than older males ( 23 , 25 ).…”

“…Notably, older patients can improve their walking speed ( 36 , 37 ), fall risk ( 36 ), and balance ( 36 ) after eccentric muscle training. However, we previously ( 26 ) observed relatively weak associations between self-selected speed during downhill walking or stair decent and eccentric knee extensor strength in healthy older adults. As we elaborate below, our walking data provide important functional context for associations between the type of muscle action and walking condition, with implications for the prescription of targeted, muscle-specific exercise interventions for older adults.…”

“…First, eccentric knee extensor and plantarflexor functions are relatively well maintained in older age. Indeed, older adults exhibit a relative maintenance of maximal voluntary eccentric strength (0%–30% loss) compared with isometric (20%–40% loss) and, in particular, concentric (30%–50% loss) strength for both muscle groups ( 23 – 26 ). Second, based on peak joint moments, the relative demand on hip and knee extensors and ankle plantarflexors to perform negative work during level and downhill walking is lower than that on the plantarflexors to perform positive work during level and uphill walking ( 18 ).…”