Biomechanical adaptations of mice cortical bone submitted to three different exercise modalities.
OBJECTIVE
To compare the adaptive effects of three non-weight bearing exercise on bone mechanical properties.


METHODS
24 male Balb/c mice (22-25g), were randomly divided into four groups (n=6): sedentary group (S); swimming group (N) which performed sessions five times per week for 60 min progressively; resistance group (R), which performed climbing exercise with progressive load, three times per week; and combined group (C), which performed the same protocols aforementioned being three times a week according to N protocol and two times a week the R protocol during eight weeks. Biomechanical tests, load until failure and stiffness evaluation of shinbone was performed after animals have been sacrificed.


RESULTS
Stiffness values were statistically higher only in the isolated modalities groups (N and R, 41.68 ± 10.43 and 41.21 ± 11.38 N/mm, respectively) compared with the S group (28.48 ± 7.34 N/mm). However, taking into consideration the final body mass, relative values, there was no difference in the biomechanical tests among the groups.


CONCLUSIONS
Data from the present investigation demonstrated a favorable influence of muscle contraction in lower impact isolated exercise modalities on absolute stiffness values, i.e.groups N and R, whereas the combined group (C) did not present any statistical significant difference compared to sedentary group. Level of Evidence II, Prospective Comparative Study .
Department of Pathology and Legal Medicine, Faculdade de Medicina de Ribeirão Preto, USP.
Fernando Tadeu Trevisan
FT
Frajacomo
Department of Pathology and Legal Medicine, Faculdade de Medicina de Ribeirão Preto, USP.
Maurício José
MJ
Falcai
Department of Pathology and Legal Medicine, Faculdade de Medicina de Ribeirão Preto, USP.
Cleverson Rodrigues
CR
Fernandes
Department of Pathology and Legal Medicine, Faculdade de Medicina de Ribeirão Preto, USP.
Antonio Carlos
AC
Shimano
Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Faculdade de Medicina de Ribeirão Preto, USP.
Sérgio Britto
SB
Garcia
Biomechanics; Exercise; Mice; Tibia