Tanvir Mustafy; Irène Londono; Florina Moldovan; Isabelle Villemure
Nature Scientific Reports, volume 9, Article number: 13128 (2019)
https://doi.org/10.1038/s41598-019-49432-2
36 citations · 11 in 2025–2026
Physical activity is beneficial for skeletal development. However, impact sports during adolescence, leading to bone growth retardation and/or bone quality improvement, remains unexplained. This study investigated the effects of in vivo low (LI), medium (MI), and high (HI) impact loadings applied during puberty on bone growth, morphometry and biomechanics using a rat model. 4-week old rats (n=30) were divided into control, sham, LI, MI, and HI groups. The impact was applied on the right tibiae, 5 days/week for 8 weeks mimicking walking (450 µe), uphill running (850 µe) and jumping (1250 µe) conditions. Trabecular and cortical parameters were determined by micro-CT, bone growth rate by calcein labeling and toluidine blue staining followed by histomorphometry. Bio-mechanical properties were evaluated from bending tests. HI group reduced rat body weight and food consumption compared to shams. Bone growth rate also decreased in MI and HI groups despite developing thicker hypertrophic and proliferative zone heights. HI group showed significant increment in bone mineral density, trabecular thickness, cortical and total surface area. Ultimate load and stiffness were also increased in MI and HI groups. We conclude that impact loading during adolescence reduces bone growth moderately but improves bone quality and biomechanics at the end of the growing period.
Equipment used
A Mach-1 system controlled a custom device applying cyclic axial loading to rat tibiae in vivo.
Figures
Figure 1 — Show caption
ANOVA test with Tukey’s multiple comparisons for structural and intrinsic mechanical properties of the right tibiae from control, sham, LI, MI and HI groups of rats derived from three-point bending tests of the mid-diaphysis. Values are expressed as Mean ± SD, N = 6/group. In the parameter column, * indicates a significant effect (p < 0.05) from a one-way ANOVA with Tukey’s multiple comparisons test. When there was a significant effect, Tukey’s post-hoc pairwise comparisons evaluated whether the sham group was significantly different compared to the other groups [a bold value and α indicate a significant difference versus sham group].
T. Mustafy. I. Londono, F. Moldovan and I. Villemure — Table 3
Figure 2 — Show caption
Impact loading setup and strain gauge calibration. (A) With the rats under anesthesia, the right tibiae from LI, MI and HI groups were loaded using a waveform generating 450, 850, and 1250 με at the medio-proximal tibial surface from the 4 to 11 week period. (B) The loading profile consisted of haversine waveform displacements at 2 Hz and characterized by symmetric loading/unloading with a 0.10 sec of rest insertion between loading cycles. Loadings were repeated for 1200 cycles, yielding a daily (5 days/week) loading period of 10 minutes. (C) Strain gauge positioned at the medio-proximal surface of the tibia for allowing strain assessment for 0.5 mm to 3.5 mm of displacement. (D) Linear relationship between applied displacement and resulting strain at the medio-proximal surface of 4, 8 and 12 week old rat tibiae (mean value ± SD) (N = 6 rats/group).
T. Mustafy. I. Londono, F. Moldovan and I. Villemure — Figure 4
Figure 3 — Show caption
Trabecular and cortical volume of interests and experimental setup for three-point bending tests. (A) Representative 3D reconstructed tibia showing the total tibial length (L). The trabecular VOI started at ~0.35 mm distal to the growth plate and extended for 12% of the overall bone length (L). The VOI for cortical bone was centered at the tibial mid-diaphysis and extended proximally and distally for 5% of the tibial length (L). Volumes of interest including only trabecular and cortical bone were semi-automatically segmented using an in-house algorithm. (B) I-Experimental setup for the three-point bending tests. A distance of 50% of the total tibial length was fixed between the supports, while the remaining 50% was distributed equally between the external sides of the supports. II-Representative image of the fractured tibia after the bending test.
T. Mustafy. I. Londono, F. Moldovan and I. Villemure — Figure 5
Materials (2)
Articular Cartilage
Bone
Test configurations (3)
Bending
Impact
