Bone mineral density and muscle strength in female ice hockey players

The purpose of this study was to investigate bone mineral density (BMD) at different sites in female ice hockey players as well as to study the relati onship between BMD, muscle strength, and body composition parameters. The s tudy group consisted of 14 female ice hockey players (age 22.2 +/- 4.3 year s) which was compared with 14 inactive females (age 21.5 +/- 3.8 years). Th e two groups were matched for age and weight. Areal bone mineral density wa s measured in total body, head, lumbar spine, femoral neck, Ward's triangle and the trochanter, using dual energy X-ray absorptiometry. Body compositi on parameters were derived from the total body scan. Isokinetic concentric peak torque of the left quadriceps and hamstrings muscles was measured usin g an isokinetic dynamometer. Compared to the inactive group, the ice hockey players had significantly higher BMD of all of the bone sites measured, ex cept for the head, (total body 6.9%, head -2.6%, lumbar spine 8.9%, femoral neck 17.6%, Ward's triangle 20.4%, and trochanter 21.7%). The hockey playe rs also had significantly higher peak torque in the quadriceps and hamstrin gs muscles. In the ice hockey group, a significant positive correlation was found between BMD of the femoral neck and hamstrings peak torque at 225 de grees/second (r = 0.67, P < 0.01). In the inactive group, significant posit ive correlations were found between BMD and peak torque in the hamstrings m uscles (90 degrees/second: r = 0.6-0.8, P < 0.05 (total body, trochanter) a nd P < 0.01 (spine, neck), 225 degrees/second: r = 0.5-0.8, P < 0.05 (total body, Ward's triangle, trochanter) and P < 0.01 (spine, neck)). In the ina ctive group significant positive correlations was also found between lean b ody mass and BMD of the trochanter (r = 0.58, P < 0.05). In young females i t appears that training and playing ice hockey might influence BMD and musc le strength in a positive direction. The correlation between BMD and muscle strength seems to weaken with increased exercise level.