Inter-Session Reliability of an Isometric Muscle Strength Protocol in Older Adults

Background: The objective of this study was to analyze the absolute and relative reliability intersession for a maximal isometric muscle strength protocol in the bilateral seated bench press (BSBP), bilateral seated row (BSR), unilateral seated knee right extension (USKER) and unilateral seated knee left extension (USKEL) in a population of older adults. Methods: Eighteen older adults (age = 69.38 ± 5.06 years; weight = 75.79 ± 14.18 kg; height = 1.61 ± 0.08 m; BMI = 28.98 ± 5.04 kg/m². The maximal isometric muscle strength assessment was performed in a seated position. Participants were asked to exert maximum effort during the exercise. The BSBP and BSR assessments were performed bilaterally with shoulders and elbows at 90°, while the USKER and USKEL assessments were performed unilaterally. Three sets of 5 secondswere performed with a 3 minutes rest between measurements until maximum isometric strength was reached in all four measurements. Results: In the inter-session reliability measurements, acceptable absolute reliability was presented for BSR and USKER, and extremely high reliability for the BSBP and USKEL measures. In addition, extremely high relative reliability was reported for all assessments of maximum isometric muscle strength, with no significant differences were observed (p > 0.05) and an ES classified as null (ES < 0.12). Conclusions: The main results of this study show that maximal isometric muscle strength in bilateral seated bench press, bilateral seated row, and unilateral seated right and left knee extension, assessed using the Chronojump Force Sensor Kit, is reliable and reproducible for the elderly population.