Continuous competitive baseball and swimming activities during youth may be associated with disk degeneration. Furthermore, the study indicates that the experience of severe low back pain might be a predictor of disk degeneration in youth. The authors hope that preventive measures and management to protect against disk degeneration and low back pain in athletes will be established by further studies based on these results.

BackgroundMuscle contraction during short intervals of intense exercise causes oxidative stress, which can play a role in the development of overtraining symptoms, including increased fatigue, resulting in muscle microinjury or inflammation. Recently it has been said that hydrogen can function as antioxidant, so we investigated the effect of hydrogen-rich water (HW) on oxidative stress and muscle fatigue in response to acute exercise.MethodsTen male soccer players aged 20.9 ± 1.3 years old were subjected to exercise tests and blood sampling. Each subject was examined twice in a crossover double-blind manner; they were given either HW or placebo water (PW) for one week intervals. Subjects were requested to use a cycle ergometer at a 75 % maximal oxygen uptake (VO2) for 30 min, followed by measurement of peak torque and muscle activity throughout 100 repetitions of maximal isokinetic knee extension. Oxidative stress markers and creatine kinase in the peripheral blood were sequentially measured.ResultsAlthough acute exercise resulted in an increase in blood lactate levels in the subjects given PW, oral intake of HW prevented an elevation of blood lactate during heavy exercise. Peak torque of PW significantly decreased during maximal isokinetic knee extension, suggesting muscle fatigue, but peak torque of HW didn’t decrease at early phase. There was no significant change in blood oxidative injury markers (d-ROMs and BAP) or creatine kinease after exercise.ConclusionAdequate hydration with hydrogen-rich water pre-exercise reduced blood lactate levels and improved exercise-induced decline of muscle function. Although further studies to elucidate the exact mechanisms and the benefits are needed to be confirmed in larger series of studies, these preliminary results may suggest that HW may be suitable hydration for athletes.

Excessive exposure to competitive sports activities during youth was associated with low back pain and symptoms in the lower extremities, with the severity varying with the sport. To reduce low back pain in youth, factors that may be causing low back pain, such as sport-specific postures and motions, need to be investigated.

Long term effect of the growing instability of the bone-implant interface due to bone resorption at the interface is a problem for the implants, including bioactive ceramics. Zn2+ -containing tricalcium phosphate (ZnTCP) is a material which may overcome this problem. The present study aims to clarify whether Zn2+ -containing tricalcium phosphate (ZnTCP) ceramics with a Zn2+ content of 0.316 (ZnTCP316) and 0.633 (ZnTCP633) wt % suppress resorption by mature osteoclasts in vitro. Suppression would be due to an increase in the number of apoptotic osteoclasts and the inhibition of the resorbing activity of osteoclasts, the latter being the major mechanism of the suppression. The number of apoptotic osteoclasts was significantly 6.3 times higher with ZnTCP633 than with tricalcium phosphate ceramic (TCP) after 24-h culture. The net contribution to resorption of this change in apoptotic cell numbers is much smaller than that of the change in resorbing activity. The osteoclasts cultured on ZnTCP formed fewer actin rings than those cultured on the TCP. The mRNA expression of CAII and cathepsin K/OC2 in the osteoclasts on ZnTCP633 was downregulated 0.5-fold and 0.6-fold, respectively, compared with that on the TCP. The volume of resorption pits was downregulated 0.4-fold in the ZnTCP633 than that in TCP. These results suggest that ZnTCPs suppressed the resorbing activity of mature osteoclasts probably through a local increase in the level of Zn2+. Bone substitutes or coating layers containing ZnTCP would be promising biomaterials from the viewpoint of counteracting osteoclastic bone resorption at the bone-implant interface.

Tension is necessary to maintain and restore the mechanical properties of soft connective tissues. Conversely, reduced tension states such as produced by immobilization weaken mechanical properties and facilitate joint contracture. We assessed the effect of low torque-long duration stretching to increase the range of motion (ROM) and to restore the mechanical properties of contracted joints in 66 rat knees immobilized for 40 days. After remobilization, we randomly divided the contracted knees into four treatment groups treated with repeated stretches of diverse torques and duration: stretching with low-torque and long-duration, high-torque and short-duration, high-torque and long-duration, low-torque and short duration. We included control and natural recovery groups. Phase lag in all treatment groups recovered to the same range as in the normal controls. Dynamic stiffness, which was not altered by joint immobilization, increased in all treatment groups. Deformation and load to failure improved substantially only in the low-torque and long-duration stretching group. Low-torque and long-duration repeated stretching leads to a greater restoration of ROM with more normal mechanical properties compared to high-torque and short duration stretching.