Bone Abstracts

Objective: Bone adapts to mechanical stimuli by increasing its mass and changing geometry; muscles are the stimulators for this change as they induce forces through contractions. Thus, bone strength is driven by muscle function. Research has shown that muscle mass and muscle function may not be proportional and hence analysing muscle function becomes of crucial importance. Here we propose to establish gender specific paediatric reference data for muscle function parameters assessed using jumping mechanography in Indian children.

Methods: The data presented here includes 562 apparently healthy Indian children (293 boys, 269 girls) aged 6 to 15 years. Children were recruited from 3 urban schools having similar (Middle to Upper) socio economic status. Participants performed 2 tests, single two legged jump and multiple one legged hopping, on a portable ground reaction force platform (Leonardo Mechanograph, Novotec).The single two legged jump is a counter movement jump with freely moving arms. The main outcome parameters of this test are maximum power (Pmax) and Pmax/mass. In multiple one legged hopping, the children were instructed to repeatedly hop on one leg. The maximum voluntary force (Fmax) and its relation to body weight Fmax/Body Weight is evaluated through this test. LMS method was used to generate age specific reference smooth curves.

Results: Pmax and Fmax were seen to be strongly dependent on age, in both the genders. Both parameters steadily increased in boys and reached a plateau in girls at around 13 years. Our children, however, showed lower maximum power and maximum voluntary force when compared with machine reference data as well as lower maximum relative power (Pmax/mass) and maximum relative force (Fmax/BW) when compared to other available reference data1. The Esslinger Fitness Index (EFI – maximum relative power normalized to age and gender) and Fmax/BW decreased with increase in age.

Conclusion: Muscle function parameters of healthy Indian children appear to be different from their western counterparts; these differences may be attributed to differences in dietary habits and physical activity. We present here reference values for muscle function by jumping mechanography in Indian children, these may be useful for the assessment of muscle function.

Disclosure: The authors declared no competing interests.