Health-related criterion-referenced cut-points for musculoskeletal fitness among youth: A systematic review

Background: Musculoskeletal fitness is an excellent functional measure that is significantly related to health among youth.

Objective: Our objective was to identify health-related criterion-referenced cut-points for musculoskeletal fitness (MSF) among youth.

Methods: A systematic search of two electronic databases (MEDLINE and SPORTDiscus) was conducted in September 2020. Only peer-reviewed studies that developed health-related criterion-referenced cut-points for MSF among youth were eligible provided they included (1) youth aged 5-17 years from the general population, (2) at least one quantitative assessment of MSF (e.g., muscular strength), (3) at least one quantitative assessment of health (e.g., cardiometabolic risk), (4) a criterion for health, and (5) a quantitative analysis [e.g., receiver operating characteristic (ROC) curve] of at least one health-related cut-point for MSF. A narrative synthesis was used to describe the results of included studies.

Results: Collectively, 13 studies that developed health-related criterion-referenced cut-points for MSF among 14,476 youth from 15 countries were included. Muscular strength demonstrated high discriminatory ability [median area under the curve (AUC) ≥ 0.71] for cardiometabolic risk/metabolic syndrome, sarcopenic obesity risk and bone health, and moderate discriminatory ability (median AUC 0.64-0.70) for asthma. Muscular power also demonstrated high discriminatory ability for bone health but only moderate discriminatory ability for cardiometabolic risk/metabolic syndrome and low discriminatory ability (median AUC 0.56-0.63) for cognition/academic performance. Both muscular endurance and flexibility demonstrated low discriminatory ability for musculoskeletal pain. Health-related cut-points for MSF that demonstrated significant discriminatory ability were generally higher for boys than for girls (for muscular strength and power) and generally increased with age for muscular strength and power but remained stable for flexibility.

Conclusions: Data remain insufficient to establish universal health-related cut-points for MSF among youth. Despite variations in the health-related discriminatory ability of different MSF tests, handgrip strength and standing broad jump emerged as the two tests with the highest discriminatory ability. More research, using standardized testing protocols and health-risk definitions, is required to better triangulate universal health-related cut-points for MSF among youth.