Isometric hip abduction and adduction strength ratios: A literature review with quantitative synthesis

BACKGROUND: Measurements of hip abduction (ABD) and adduction (ADD) are important in strength and conditioning as well as in clinical practice. However, there is no clear consensus on how ABD and ADD compare in strength in different populations. OBJECTIVE: The aim was to perform a quantitative synthesis of comparisons between the isometric strength of ABD and ADD in different populations. METHODS: ABD and ADD strength data were collected and pooled mean values for ABD: ADD strength ratio were calculated and expressed as standardized mean differences. Forty studies of healthy adults, 5 studies of healthy older adults and 14 studies of adults with various musculoskeletal injuries were included in the analysis. RESULTS: Healthy (non-athletic) males, healthy older adults, and adults with hip and groin pathologies or osteoarthritis tend to have the same ADD and ABD strength; male athletes tend to have a stronger ADD compared with ABD; healthy females and adults with patellofemoral pain tend to have a stronger ABD compared with ADD. CONCLUSIONS: These results can serve as a database to help compare and interpret measurements of ADD and ABD strength ratio in different populations.