The purpose of the study was to assess maximum voluntary forefoot ground reaction force during multiple one-legged hopping (Fm1LH) and to determine the correlation between tibial volumetric bone mineral content (vBMC, a valid surrogate of bone strength) and Fm1LH.Methods:
One hundred eighty-five females (8-82 yr old) and 138 males (8-71 yr old) performed multiple one-legged hopping to measure Fm1LH acting on the forefoot during landing. Peripheral quantitative computed tomography scans were obtained to assess vBMC at 4%, 14%, 38%, and 66% of tibia length and calf muscle cross-sectional area at the 66% site.Results:
In all 323 participants, Fm1LH corresponded to 3-3.5 times body weight, and Fm1LH predicted vBMC14% by 84.0% (P < 0.001). vBMC14% was better correlated with Fm1LH than with the calf muscle cross-sectional area in both males (R2 = 0.841 vs R2 = 0.724) and females (R2 = 0.765 vs R2 = 0.597). Fm1LH and vBMC14% both increased during growth and afterward remained constant or decreased with age but never increased above the values reached at the end of puberty. Fm1LH decreased by 23.6% between 21-30 and 61-82 yr in females and by 14.0% between 31-40 and 51-71 yr in males. vBMC14% decreased by 13.7% in females between 21-30 and 61-82 yr but remained unchanged in adult males.Conclusions:
Multiple one-legged hopping yields the highest (i.e., maximum) ground reaction force relative to other jumping maneuvers. Because bone strength is strongly governed by maximum muscle force, the concurrent assessment of peripheral quantitative computed tomography-derived bone strength and Fm1LH might represent a new approach for the operational evaluation of musculoskeletal health.