To compare the role of familiarization performed up to 10 days before the main assessment of muscle power in the lower limb muscles using an isokinetic dynamometer.
This is a cross-sectional study. Two assessments of lower limb muscle power (hip flexion, extension, abduction, and adduction; knee flexion and extension; ankle plantar flexion and dorsiflexion) were performed using the isokinetic dynamometer (Biodex System Pro 4), with a maximum interval of 10 days between assessments: familiarization (T0) and main assessment (T1). The study was approved by the Research Ethics Committee (CAAE: 69062323.5.0000.5440). A repeated measures Student's t-test was conducted for all muscle groups to investigate the differences in muscle power values between the two time points. The data were transformed following the Templeton method due to non-normal distribution. After the transformation, the Kolmogorov-Smirnov test confirmed the normality of the data. The significance level was set at 5%. The difference in values obtained from the two time points was calculated as ∆ = T1 – T0. For interpreting the results, effect sizes (Cohen's d) were considered as small (≥ 0.21 and 0.39), medium (≥ 0.40 and 0.79), and large (≥ 0.80).
The study included 59 community-dwelling older adults, with 73% (n=43) being female and 27% (n=16) male, with a mean age of 68.67 (6.01) years. The results indicated that muscle power values were higher on the second assessment day for the following muscle groups: hip flexors (∆ = 7.88, p 0.001, Cohen's d = 0.69), hip extensors (∆ = 11.95, p 0.001, Cohen's d = 0.81), hip abductors (∆ = 6.94, p 0.005, Cohen's d = 0.42), hip adductors (∆ = 7.09, p 0.001, Cohen's d = 0.67), knee flexors (∆ = 14.35, p 0.001, Cohen's d = 0.53), knee extensors (∆ = 9.19, p 0.001, Cohen's d = 0.33), and ankle plantar flexors (∆ = 5.38, p 0.001, Cohen's d = 0.68). However, no significant increase in muscle power was observed for the ankle dorsiflexors (∆ = 0.15, p = 0.77, Cohen's d = 0.03) despite a small effect size for this group.
The analyses demonstrated that muscle power familiarization for hip flexors and extensors, hip abductors and adductors, knee flexors and extensors, and ankle plantar flexors play a crucial role in practice-based improvement, linked to the effects of motor learning.
Our results emphasize the importance of familiarization in muscle power testing for obtaining reliable data in older adults, highlighting its implications for physiotherapy.
Muscle function
Protocol
