Ability of Isokinetic Dynamometer to Predict Isotonic Knee Extension 1-Repetition Maximum

Abstract

Context: Resistance training exercise prescription is often based on exercises performed at a percentage of a 1-repetition maximum (1RM). Following knee injury, there is no consensus when a patient can safely perform 1RM testing. Resistance training programs require the use of higher loads, and loads used in knee injury rehabilitation may be too low to elicit gains in strength and power. A maximum isometric contraction can safely be performed during early stages of knee rehabilitation and has potential to predict an isotonic knee extension 1RM. Objective: To determine whether a 1RM on an isotonic knee extension machine can be predicted from isometric peak torque measurements. Design: Descriptive laboratory study. Setting: University research laboratory. Participants: A total of 20 (12 males and 8 females) healthy, physically active adults. Main Outcome Measures: An isokinetic dynamometer was used to determine isometric peak torque (in N·m). 1RM testing was performed on a knee extension machine. Linear regression was used to develop a prediction equation, and Bland–Altman plots with limits of agreement calculations were used to validate the equation. Results: There was a significant correlation (P < .001, r = .926) between peak torque (283.0 [22.6] N·m) and the knee extension 1RM (69.1 [22.6] kg). The prediction equation overestimated the loads (2.3 [9.1] kg; 95% confidence interval, −15.6 to 20.1 kg). Conclusions: The results show that isometric peak torque values obtained on an isokinetic dynamometer can be used to estimate 1RM values for isotonic knee extension. Although the prediction equation tends to overestimate loads, the relatively wide confidence intervals indicate that results should be viewed with caution.

Development and Validation of a Leg Press Force Measuring Device to Assess Limb Strength Asymmetry

“…[21][22][23][24][25] For strength testing, although a variety of methods are available, the most commonly used are either handheld dynamometry or isokinetic dynamometer metrics. [26][27][28] However, although the leg press is one of the more commonly employed strength testing exercises to maintain and increase quadriceps strength, force production data are limited to the amount of weight lifted. Similarly, although the leg press device has shown promise for unilateral assessments and their relationship to hop testing and isokinetic torque values, 29 current assessments are not capable of assessing individual limb contributions during a bilateral leg press exercise.…”

Assessment of Force Through Lactate as a Measure to Quantify the Training Load in Populations With Risk Factors

“…Para la cuantificar la fuerza desde la década de 1980 se han realizado varios estudios con el objetivo de establecer valores de referencia de fuerza muscular utilizando para este fin diferentes métodos y elementos de medición, (Bäckman et al, 1989;Bäckman et al, 1995;Decostre et al, 2015;McKay et al, 2017;Benfica et al, 2018;Resende et al, 2020;(Dornas et al, 2023). Actualmente la evidencia propone evaluación a través de una repetición máxima (1Rm) y/o con ecuaciones que determinan un valor submaximo (Lesnak et al, 2020). acompañados, Además, escalas de percepción subjetiva de esfuerzo y escalas OMNI-RES (Borg & Kaijser, 2006;(Pfeiffer et al, 2002).…”