Abstract

PURPOSE:: To assess maximum voluntary forefoot ground reaction force (Fm1LH) during multiple one-legged hopping (m1LH, a new jumping maneuver) and to determine the correlation between tibial volumetric bone mineral content (vBMC, a valid surrogate of bone strength) and Fm1LH. METHODS:: One hundred and eighty-five females (8-82 years old) and 138 males (8-71 years old) performed m1LH to measure Fm1LH acting on the forefoot during landing. Peripheral quantitative computed tomography (pQCT) scans were obtained to assess vBMC at 4, 14, 38 and 66% tibia length and calf muscle cross-sectional area (Ar.muscle) 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 Ar.muscle in both males (R = 0.841 vs. R = 0.724) and females (R = 0.765 vs. R = 0.597). Fm1LH and vBMC14% both increased during growth and afterwards 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 years in females and by 14.0% between 31-40 and 51-71 years in males. vBMC14% decreased by 13.7% in females between 21-30 and 61-82 years but remained unchanged in adult males. CONCLUSIONS:: m1LH yields the highest (i.e. maximum) ground reaction force relative to other jumping maneuvers. Since bone strength is strongly governed by maximum muscle force, the concurrent assessment of pQCT-derived bone strength and Fm1LH might represent a new approach for the operational evaluation of musculoskeletal health.