Hamstring muscle strain is the most prevalent injury in Australian Rules Football, accounting for 16% of playing time missed as a result of injury. Thirty-seven professional footballers from an Australian Football League team had preseason measurements of hamstring and quadriceps muscle concentric peak torque at 60, 180, and 300 deg/sec measured on a Cybex 340 dynamometer. Players were studied prospectively throughout the 1995 season. During that time, six players sustained clinically diagnosed hamstring muscle injuries that caused them to miss match-playing time. The injured hamstring muscles were all weaker than in the opposite leg in absolute values and hamstring-to-quadriceps muscle ratios. According to our t-test results, hamstring muscle injury was significantly associated with a low hamstring-to-quadriceps muscle peak torque ratio at 60 deg/sec on the injured side and a low hamstring muscle side-to-side peak torque ratio at 60 deg/sec. Flexibility (as measured by the sit-and-reach test) did not correlate with injury. Discriminant-function analysis using the two significant ratio variables resulted in a canonical correlation with injury of 0.4594 and correctly classified legs into injury groups with 77.4% success. These results indicate that preseason isokinetic testing of professional Australian Rules footballers can identify players at risk of developing hamstring muscle strains.
Objectives-To investigate the prevalence of inguinal canal posterior wall deficiency (sports hernia) in professional Australian Rules footballers using an ultrasound technique and correlate the results with the clinical symptom of groin pain. Methods-Thirty five professional Australian footballers with and without groin pain were investigated blind with a dynamic high resolution ultrasound technique for presence of posterior wall deficiency. Results-Fourteen players had a history of significant recent groin pain and ten of these were found to have bilateral inguinal canal posterior wall deficiency (p<0.01). The relative risk for a history of groin pain with bilateral deficiency was 8.0 (95% confidence interval 1.73 to 37.1). Groin pain was also found to be associated with increasing age (p<0.01) which was an independent risk factor. Surgical, clinical, and ultrasound follow up for players who underwent hernia repair confirmed the validity of ultrasound as a diagnostic tool. Conclusions-Dynamic ultrasound examination is able to detect inguinal canal posterior wall deficiency in young males with no clinical signs of hernia. This condition is very prevalent in professional Australian Rules footballers, including some who are asymptomatic. There was a correlation between bilateral deficiency and groin pain, although the temporal relationship between the clinical and ultrasound findings is not established by the current study. Ultrasound shows promise as a diagnostic tool in athletes with chronic groin pain who are considered possible candidates for hernia repair. (Br J Sports Med 1998;32:134-139)
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SUMMARY1. An isolated gastrocnemius muscle from cat was perfused with a modified Ringer fluid containing the extracellular tracers mannitol, sucrose and inulin and in some cases tritiated water (HTO). When equilibration of the tracers between the perfusate and the tissue was obtained, perfusion with tracer-free fluid was started.2. The fractional rate of escape, 1D (t), of the tracers was followed. For all tracers it declined steadily with time. The rate of decline was faster for the smaller extracellular molecules when any combination of two extracellular tracers was studied.3. Arrest of flow for 1-2 min lead to an increase in (D (t) for the extracellular tracers when flow was resumed. There was little or no effect upon () (t) for HTO.4. Doubling the rate of flow had no effect upon (D (t) for the extracellular tracers, while that of HTO increased.5. We conclude that the cause of the decline in (D (t) for the extracellular tracers is concentration gradients in the interstitial space. The findings raise problems in methods for studying capillary permeability by means of the fractional rate of escape of tracers from the interstitial space into the vascular system.
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