Related Experiment Video
Updated: Sep 20, 2026
Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
Assessment and interpretation of isokinetic muscle strength during growth and maturation
Mark De Ste Croix1, Martine Deighan, Neil Armstrong
1Children's Health and Exercise Research Centre, School of Sport and Health Sciences, University of Exeter, Exeter, UK. m.b.a.de-ste-croix@exeter.ac.uk
Insights
Isokinetic strength testing in children is reliable for knee movements but needs more research for upper body dynamics. Factors like age, body size, and composition influence strength, but other elements remain unclear.
Area of Science:
- Pediatric Exercise Science
- Biomechanics
- Human Growth and Development
Background:
- Most pediatric strength studies use isometric actions, limiting understanding of dynamic muscle function.
- Isokinetic testing in children presents methodological challenges, though reliability for knee movements is established.
- Limited data exist on upper body isokinetic strength and its development during childhood.
Purpose of the Study:
- To review current knowledge on isokinetic strength development in children.
- To identify gaps in research regarding pediatric isokinetic strength testing and influencing factors.
- To highlight the need for further investigation into upper body strength, sex differences, and maturation effects.
Main Methods:
- Literature review of existing studies on pediatric isokinetic strength.
- Analysis of data concerning age, sex, body size, and composition effects.
- Identification of methodological limitations and areas requiring further research.
Main Results:
- Isokinetic strength generally increases with age, but underlying mechanisms require more study.
- Reliable isokinetic assessment is possible in children, particularly for knee joints.
- Stature, body mass, and fat-free mass are significant predictors of isokinetic strength, but unexplained variance remains.
Conclusions:
- Further research is needed on upper body isokinetic strength reliability and development in children.
- Longitudinal studies are recommended to explore maturation, sex differences, and qualitative muscle changes.
- Understanding factors beyond body composition is crucial for a complete picture of pediatric strength development.
Abstract:
The majority of strength studies examining changes during growth and maturation have investigated isometric actions, which tell us little about the muscle under dynamic conditions. There are numerous methodological issues in the isokinetic testing of paediatric populations that require further investigation. However, several studies have indicated that children can be reliably assessed isokinetically using both concentric and eccentric actions. Most paediatric studies have examined the knee joint and more data are needed to elucidate the reliability of upper body isokinetic strength testing. The age- and sex-associated development of isokinetic strength is less well understood. Studies have indicated that isokinetic strength increases with age but the mechanisms associated with this increase require further investigation. Current data are also conflicting regarding the age at which sex differences become apparent in isokinetic strength. More work is needed to examine the influence of maturation on isokinetic strength development, but available data suggest that maturation is a non-significant contributory factor once stature and body mass are accounted for. Most studies have demonstrated a significant relationship between stature, body mass and isokinetic strength during growth and maturation. The importance that changes in body composition during growth have on isokinetic strength has been investigated using fat-free mass and muscle cross-sectional area. Data have shown that although fat-free mass and muscle cross-sectional area are important contributors to isokinetic strength, other unexplained factors also influence isokinetic strength development. Additional work needs to investigate possible qualitative changes in muscle during growth and maturation. More work is also needed to examine changes in eccentric strength with age and to investigate sex differences in upper body isokinetic strength. Future studies should preferably be longitudinal in nature and examine known covariates simultaneously using appropriate statistical techniques.
