Abstract
Compensatory reserve measurement (CRM) is a metric of all physiological mechanisms that sustain adequate oxygen perfusion to working muscles. We hypothesized that CRM would track muscular fatigue. PURPOSE: To assess patterns of CRM and muscular torque output during repeated maximal effort fatiguing muscular contractions and during recovery and to examine the relationship between CRM and torque output. METHODS: Twenty-nine healthy physically active participants (age: 21.9 ± 0.4 yr) performed a muscular fatigue task consisting of 4 sets (S) x 20 repetitions (R) of maximal isometric knee extension contractions on an isokinetic dynamometer. Each contraction was held 10s with a 2s rests between contractions and a 2-min recovery (REC) period following each set. CRM was obtained following the first (R1) and last (R20) repetition of each set and at the end of each REC period using a sensor placed on the participant’s index finger. Mean torque during R1 and R20 of each set was measured and normalized (%) to the first contraction of the fatigue task. Torque and CRM during the fatigue task and CRM REC were analyzed using repeated measures ANOVA and reported as mean ± SE with statistical significance set at p < 0.05. An amalgamated Pearson’s correlation coefficient (R2) between CRM and mean torque was performed using subject group averages for R1 and R20 of each set. RESULTS: During the fatigue task, mean torque decreased (p < 0.001) from R1 to R20 for all sets (S1: 100 ± 0%, 47 ± 3%; S2: 73 ± 3%, 42 ± 2%; S3: 64 ± 3%, 41 ± 3%; S4: 58 ± 3%, 42 ± 3%). During the fatigue task, CRM also decreased from R1 to R20 for all sets (S1: 63 ± 4%, 48 ± 3%, p < 0.001; S2: 61 ± 4%, 45 ± 3%, p < 0.001; S3: 57 ± 4%, 46 ± 3%, p = 0.001; S4: 56 ± 4%, 46 ± 3%, p = 0.02). Mean torque was higher (p < 0.001) during S1R1 compared to R1 for all other sets. CRM during S1R1 was similar to R1 for S2 (p = 0.5) but decreased for S3 (p = 0.04) and S4 (p = 0.03). Compared to R20, CRM REC returned toward R1 levels (p < 0.01) after each set (S1: 59 ± 4%; S2: 56 ± 4; S3: 55 ± 4%; S4: 60 ± 4%). REC S1 was greater (p ≤ 0.01) than REC S2 and S3 but was not different than S4 (p = 0.37). During the muscular fatigue task, there was a positive correlation between CRM and mean torque output (R2 = 0.94). CONCLUSION: CRM and torque response followed similar patterns during a muscular fatiguing task and recovery. The positive correlation between CRM and mean torque suggests CRM may be a viable tool to evaluate skeletal muscle fatigue during exercise.
Recommended Citation
Joe, Claudette; Ferguson, Antoine; Khan, Khizra; Khadka, Barsha; Convertino, Victor Ph.D.; and Mettler, Joni A. Ph.D.
(2026)
"Compensatory Reserve Measurement: A Tool to Assess Skeletal Muscle Fatigue,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
18, Article 131.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss18/131
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