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EP-01 Fitness Assessment, Exercise Training, and Performance of Athletes and Healthy People

Utility Of Strength-based Torque Characteristics To Distinguish Between Older Women Of Different Walking Performance Abilities

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Palmer, Ty B.; Blinch, Jarrod; Farrow, Ahalee C.; Agu-Udemba, Chinonye C.; Mitchell, Ethan A.

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Medicine & Science in Sports & Exercise: August 2021 - Volume 53 - Issue 8S - p 2
doi: 10.1249/01.mss.0000759032.72426.84
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Maximal and rapid strength measurements, such as peak torque (PT) and rate of torque development (RTD), play an important role in gait speed and timed up-and-go performances; however, few studies have investigated the ability of these measurements to characterize functional differences in older adults according to their performance on a six-minute walk test.

PURPOSE: This study aimed to examine the effectiveness of isometric PT and RTD characteristics of the knee extensors to differentiate between older women who are able (higher functioning [HF]) versus those who are unable (lower functioning [LF]) to walk 550 m in six minutes.

METHODS: Ten HF (67 ± 4 years) and 10 LF (68 ± 4 years) older women performed three single-leg, isometric knee extension maximal voluntary contractions (MVCs) followed by a six-minute walk test. For each MVC, participants sat in an upright position and were instructed to extend the leg “as hard and fast as possible” for 3-4 s. Isometric PT and early (RTD100), late (RTD200), and maximum (Peak RTD) RTD measurements were calculated and displayed by a novel strength testing device at the conclusion of each MVC and were normalized to body mass. The total distance covered (m) during the six-minute walk test was recorded and used to separate the participants into higher (≥550 m) or lower (<550 m) functioning groups.

RESULTS: The HF group exhibited greater PT (HF = 1.82 ± 0.30 Nm·kg-1; LF = 1.45 ± 0.28 Nm·kg-1; P = 0.011), Peak RTD (HF = 12.35 ± 2.43 Nm·s-1·kg-1; LF = 6.32 ± 1.71 Nm·s-1·kg-1; P < 0.001), RTD100 (HF = 11.88 ± 2.49 Nm·s-1·kg-1; LF = 5.36 ± 1.97 Nm·s-1·kg-1; P < 0.001), and RTD200 (HF = 7.69 ± 1.20 Nm·s-1·kg-1; LF = 4.62 ± 1.03 Nm·s-1·kg-1; P < 0.001) than the LF group, with larger differences occurring for the RTD characteristics (39.9-54.9%) than PT (20.3%). There were significant positive relationships between six-minute walk distance and the PT and RTD characteristics (r = 0.554-0.661; P = 0.002-0.011).

CONCLUSION: These findings suggest that knee extensor muscle strength, and in particular RTD, may be an effective measure at distinguishing between older women of different six-minute walking performance abilities. Physical therapists and other practitioners may use these findings to help with the identification and early detection of older adults who are at a high risk for functional performance deficits.

Copyright © 2021 by the American College of Sports Medicine