Eccentric Peak Torque is Related to Fall Risk in Physically Active Older Adults

Abstract

It is well-known that lower extremity weakness, commonly expressed as a reduction in isometric or concentric strength, is associated with fall risk in older adults. It is also understood that successful completion of functional tasks requires a minimum threshold of eccentric strength. However, data is sparse concerning the relationship between isokinetic eccentric strength and fall risk. PURPOSE: To compare activities-specific balance confidence (ABC) and isokinetic peak torque (PT) in physically active older adults. METHODS: Ninety-eight physically active, community dwelling men and women were recruited and divided into two groups: Fallers (F; n=21, 66±8 yr, 76±17 kg) and Non-Fallers (NF; n=77, 65±8 yr, 75±15 kg). All participants completed the Berg Balance Test (BBT), ABC scale, and measurement of isokinetic PT. PT was recorded at two velocities (60°/s and 180°/s) with two contraction modes (concentric and eccentric) on a Biodex isokinetic dynamometer for two muscle groups: knee extensors and knee flexors. RESULTS: One-way ANOVA revealed no significant group differences for age, self-reported physical activity frequency or intensity, or body mass index. Despite these baseline similarities, F had significantly lower ABC (81 vs. 93; p<0.001) and eccentric PT in knee flexors at 180°/s (193 vs. 241 n·M; p<0.05) as compared to NF. Although not statistically significant, F had lower PT values in three other eccentric measures (11-14% lower) and all four concentric PT measures (9-15% lower). CONCLUSIONS: Despite similar levels of physical activity and BBT scores, F had lower balance confidence and lower isokinetic eccentric PT than NF. These data suggest that lower limb eccentric PT may be an important factor in understanding fall risk in active older adults.