title: Endurance time is joint-specific: a modelling and meta-analysis investigation.
abstract: Static task intensity-endurance time (ET) relationships (e.g. Rohmert's curve) were first reported decades ago. However, a comprehensive meta-analysis to compare experimentally-observed ETs across bodily regions has not been reported. We performed a systematic literature review of ETs for static contractions, developed joint-specific power and exponential models of the intensity-ET relationships, and compared these models between each joint (ankle, trunk, hand/grip, elbow, knee, and shoulder) and the pooled data (generalised curve). 194 publications were found, representing a total of 369 data points. The power model provided the best fit to the experimental data. Significant intensity-dependent ET differences were predicted between each pair of joints. Overall, the ankle was most fatigue-resistant, followed by the trunk, hand/grip, elbow, knee and finally the shoulder was most fatigable. We conclude ET varies systematically between joints, in some cases with large effect sizes. Thus, a single generalised ET model does not adequately represent fatigue across joints. STATEMENT OF RELEVANCE: Rohmert curves have been used in ergonomic analyses of fatigue, as there are limited tools available to accurately predict force decrements. This study provides updated endurance time-intensity curves using a large meta-analysis of fatigue data. Specific models derived for five distinct joint regions should further increase prediction accuracy.
authors.affiliation: Graduate Program in Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA, USA.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Frey Law
authors.forename: Keith G
authors.initials: KG
authors.lastname: Avin
mesh_terms: D001696:Biomechanical Phenomena; D006801:Humans; D007596:Joints / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*