Validity, Reliability, and Sensitivity to Change of DiCI for the Strength Measurement of Knee and Hip Muscles

Many professionals use the handheld dynamometers (HHDs) to assess isometric strength. This study aimed to evaluate the validity, reliability, and sensitivity to change of a DiCI (a new HHD) for the strength measurement of knee and hip muscles and their ratios. Thirty-five recreational athletes completed quadriceps, hamstring, and hip adductors and abductors strength tests in two identical sessions with 1-week interval between them. A fatigue test was carried out for the quadriceps and hamstring. Consistency between DiCI and MicroFet2 was excellent (r > 0.939) for all strength tests. Relative reliability analysis showed good to excellent ICCs (ICC's isolated muscle range = 0.93 to 0.96 and ICC's ratios range = 0.70 to 0.82). Sensitivity to change showed large change magnitudes for quadriceps and hamstring fatigue (-1.89 and -1.26, respectively). DiCI is valid and reliable to assess knee and hip strength and sensitive to fatigue change.