Context: As the Asian Ice Hockey League gradually expands and becomes more competitive, ice hockey-related injuries may increase. However, no reports have been published on ice hockey injuries in Japan, including the method of injury and the daily supervision of the players during the regular season.Objective: To prospectively study the incidence, types, and mechanisms of ice hockey injuries in an elite Japanese ice hockey team.Design: Prospective observational cohort study design. Main Outcome Measure(s): Data were collected for 3 consecutive seasons using an injury reporting form.Results: The overall game injury rate was 74.3 per 1000 player-game hours and 11.7 per 1000 player-game hours for injuries resulting in any time loss. The overall practice injury rates were 11.2 per 1000 player-practice hours and 1.1 per 1000 player-practice hours for injuries resulting in any time loss. Forwards had the highest rate of injury, followed by defensemen and then goalkeepers. Contusions were the most common injury, followed by strains, lacerations, and sprains.Conclusions: Most injuries among Japanese ice hockey players occurred during games. Game or play intensity may influence the injury rate during games.Key Words: injury rates, epidemiology, injury surveillance Key PointsN Most injuries occurred during games, which were associated with greater play intensity than practices. N Forwards demonstrated the highest rate of injury, followed by defensemen and then goalkeepers. N The most common injuries were contusions, strains, lacerations, and sprains.

Lumbar spondylolysis in elementary school age children was commonly a terminal-stage bone defect at L5, which was not necessarily related to history of athletic activity and was sometimes asymptomatic. It was often associated with SBO, indicating a possible congenital predisposition. These findings may provide further insight into the pathogenesis of lumbar spondylolysis.

The present study showed that inflammation was always present at the pars defects and in some cases at the adjoining facet joints. Thus, it is not difficult to understand how, during sports activity, inflammation may first occur at the pseudoarthrotic site and then spread to the adjoining facet joints. This mechanism could cause LBP associated with terminal-stage (pseudoarthrotics) spondylolysis in athletes.

Tight hamstrings are reported to be one of the causes of low back pain. However, there have been few reports on effective stretching procedures for the tight hamstrings. The so-called jack-knife stretch, an active-static type of stretching, can efficiently increase the flexibility of tight hamstrings. To evaluate hamstring tightness before and after the 4-week stretching protocol in healthy volunteer adults and patients aged under 18 years with low back pain. For understanding the hamstrings tightness, we measured two parameters including (1) finger to floor distance (FFD) and (2) pelvis forward inclination angle (PFIA). Eight healthy adult volunteers who had no lumbar or hip problems participated in this study (mean age: 26.8 years). All lacked flexibility and their FFD were positive before the experiment. Subjects performed 2 sets of the jack-knife stretch every day for 4 weeks. One set consisted of 5 repetitions, each held for 5 s. Before and during the 4-week experiment, the FFD and PFIA of toe-touching tests were measured weekly. For 17 of the sports players aged under 18, only FFD was measured. In adult volunteers, FFD was 14.1 ± 6.1 cm before the experiment and decreased to -8.1 ± 3.7 cm by the end of week 4, indicating a gain in flexibility of 22.2 cm. PFIA was 50.6 ± 8.2 before the experiment and 83.8 ± 5.8 degrees after. Before and after the experiment, the differences were significant (p < 0.05). For those aged under 18, FFD was 8.1 ± 8.0 and -9.6 ± 6.8, before and after the stretching, respectively. This difference was significant (p < 0.05). The jack-knife stretch is a useful active-static stretching technique to efficiently increase flexibility of tight hamstrings.

: Background : It was reported that hamstring muscle tightness may increase mechanical loading on the lumbar spine. Therefore, we attempt to decrease tightness in the leg muscles in pediatric patients. Methods : Forty-six pediatric patients with spondylolysis underwent rehabilitation. We applied active stretching to the hamstrings, quadriceps, and triceps surae. Tightness in each muscle was graded as good, fair, or poor. We educated each patient on how to perform active stretching at home. They were re-evaluated for muscle tightness 2 months later. Results : Tightness at baseline and after 2 months was as follows : for the hamstrings, good in 3 patients, fair in 9, and poor in 34 and significant improved after 2 months (p 0.05), with improvement by least 1 grade seen in 86% % of patients with fair or poor at baseline ; for the quadriceps, 7, 3, and 30 patients had good, fair and poor, with significant improvements in 72% % (p 0.05). For the triceps surae, 6, 3 and 10 patients had good, fair and poor, which improved significantly (p 0.05). Conclusion : Home-based active stretching was effective for relieving muscle tightness in the leg in a pediatric population. Adolescent athletes should perform such exercise to maintain flexibility and prevent lumbar disorders.