Measurement of fatigue in knee flexor and extensor muscles.
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In order to examine fatigue of the knee flexor and extensor muscles and to investigate the characteristics of muscular fatigue in different sports, a Cybex machine was used to measure muscle fatigue and recovery during isokinetic knee flexion and extension. Eighteen baseball players, 12 soccer players and 13 marathon runners were studied. Each subject was tested in the sitting position and made to perform 50 consecutive right knee bends and stretches at maximum strength. This was done 3 times with an interval of 10 min between each series. The peak torque to body weight ratio and the fatigue rate were determined in each case. In all subjects, the peak torque to body weight ratio was higher for extensors than flexors. Over the 3 trials, the fatigue rate of extensors showed little change, while that of flexors had a tendency to increase. In each subject, knee extensors showed a high fatigue rate but a quick recovery, while knee flexors showed a low fatigue rate but a slow recovery. As the marathon runners had the smallest fatigue rates for both flexors and extensors, we concluded that marathon runners had more stamina than baseball players and soccer players. (+info)
Spit (smokeless) tobacco use by high school baseball athletes in California.
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OBJECTIVE: To describe the prevalence, patterns, and correlates of spit (smokeless) tobacco (ST) use in a sample of high school baseball athletes in California. DESIGN: This cross sectional study was a survey of 1226 baseball athletes attending 39 California high schools that were randomly selected from a list of all publicly supported high schools with baseball teams. At a baseball team meeting, athletes who agreed to participate and had parental consent completed the study questionnaire. To enhance the accuracy of self reported ST use status, a saliva sample was collected from each subject. The questionnaires and saliva samples were coded and salivary cotinine assay was performed on a random subsample of 5% of non-users who also were non-smokers. Biochemical assay indicated that 2% tested positive for cotinine inconsistent with self reported ST non-use. RESULTS: Overall, 46% had ever used ST and 15% were current users. Odds ratios and 95% confidence intervals (CI) suggested that, among high school baseball athletes, age, living in a rural area, being white, smoking cigarettes, drinking alcohol, not knowing about the adverse effects of ST, perceiving little personal risk associated with ST use, and believing that friends, role models, teammates, and same age baseball athletes in general used ST, increased the likelihood of being an ST user. CONCLUSION: The findings indicate that considerable experimentation with ST products occurs among high school baseball athletes in California, and many are current users. ST interventions targeting this population are needed to stop the transition from experimental ST use to tobacco dependence. Correlates of ST use for consideration in future intervention studies are identified. (+info)
Acceptability of baseball face guards and reduction of oculofacial injury in receptive youth league players.
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GOALS: To assess the relative injury reduction effect and acceptability of face guards on batter's helmets. METHODS: A non-randomized prospective cohort study among 238 youth league baseball teams in Central and Southern Indiana during the 1997 season. Coaches, parents, and players were asked to respond to pre-season and post-season questionnaires. Approximately one half of the teams were supplied with face guard helmets (intervention); all others used this protection at their discretion (comparison). RESULTS: Parents, players, and coaches on the intervention teams reported a reduction in the incidence of oculofacial injuries compared with comparison team respondents (p=0.04). There was no reported adverse effect of face guard use on player performance. CONCLUSIONS: Helmet face guards should be required for batters to prevent facial injuries in baseball. (+info)
Impact directly over the cardiac silhouette is necessary to produce ventricular fibrillation in an experimental model of commotio cordis.
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OBJECTIVES: In an experimental model of sudden death from chest wall impact (commotio cordis), we sought to define the chest wall areas important in the initiation of ventricular fibrillation (VF). BACKGROUND: Sudden death can result from an innocent chest blow by a baseball or other projectile. Observations in humans suggest that these lethal blows occur over the precordium. However, the precise location of impact relative to the risk of sudden death is unknown. METHODS: Fifteen swine received 178 chest impacts with a regulation baseball delivered at 30 mph at three sites over the cardiac silhouette (i.e., directly over the center, base or apex of the left ventricle [LV]) and four noncardiac sites on the left and right chest wall. Chest blows were gated to the vulnerable portion of the cardiac cycle for the induction of VF. RESULTS: Only chest impacts directly over the heart triggered VF (12 of 78: 15% vs. 0 of 100 for noncardiac sites: p < 0.0001). Blows over the center of the heart (7 of 23; 30%) were more likely to initiate VF than impacts at other precordial sites (5 of 55; 9%, p = 0.02). Peak LV pressures generated instantaneously by the chest impact were directly related to the risk of VF (p < 0.0006). CONCLUSIONS: For nonpenetrating, low-energy chest blows to cause sudden death, impact must occur directly over the heart. Initiation of VF may be mediated by an abrupt and substantial increase in intracardiac pressure. Prevention of sudden death from chest blows during sports requires that protective equipment be designed to cover all portions of the chest wall that overlie the heart, even during body movements and positional changes that may occur with athletic activities. (+info)
Extra-anatomic bypass graft for management of axillary artery occlusion in pitchers.
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OBJECTIVE: Our goal was to evaluate the long-term results of vein bypass grafts for axillary artery occlusion, specifically those placed extra-anatomically to prevent arterial injury in pitchers. METHODS: With the greater saphenous veins used as the selected conduit, arterial bypass grafts were routed anterior to the pectoralis minor muscle in four baseball pitchers who had occlusion of the axillary artery. We performed a follow-up in excess of 10 years with evaluations of the bypass grafts by ultrasonic duplex scan and magnetic resonance angiography. RESULTS: All four pitchers treated in this manner returned to the game and played for several seasons without a recurrence of the arterial injury. Long-term evaluation of the bypass grafts did not reveal any structural or functional disorder. CONCLUSIONS: Axillary artery occlusion in an athlete can be effectively treated with a vein bypass graft placed extra-anatomically, anterior to the pectoralis minor muscle. The greater saphenous vein should be considered the conduit of choice. (+info)
Two cases of peroneus brevis tendon tear.
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A longitudinal tear of the peroneal tendon is thought to be the result of repetitive peroneal subluxation. However, this report documents two cases of longitudinal split of the peroneus brevis tendon that had no peroneal tendon subluxation. Primary suture was performed. Subluxation of the peroneal tendons was not identified surgically in either case. (+info)
Oral screening and brief spit tobacco cessation counseling: a review and findings.
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This paper reviews five randomized controlled trials of brief spit (smokeless) tobacco (ST) cessation treatment by dental professionals consisting of oral cancer screening, cessation advice, self-help materials, and brief cessation counseling by a dental hygienist. In addition, original two-year findings from a randomized controlled trial to determine the effect of a dental-directed, peer-assisted ST intervention among high school baseball athletes in rural California (n=1084) are reported. In the latter study, results show sustained quitting at two years of 23 percent (32/141) in the intervention group and 13 percent (21/166) in the control group (OR=2.0, 95% CI 1.1-3.9) with subjects lost-to-follow-up considered non-quitters. The evidence presented supports the efficacy of oral screening and brief cessation counseling by dental professionals to promote ST cessation in the dental office or in athletic facilities. In addition, recommendations for policy and future research are presented. (+info)
Upper and lower limits of vulnerability to sudden arrhythmic death with chest-wall impact (commotio cordis).
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OBJECTIVES: In an animal model of commotio cordis, sudden death with chest-wall impact, we sought to systematically evaluate the importance of impact velocity in the generation of ventricular fibrillation (VF) with baseball chest-wall impact. BACKGROUND: Sudden cardiac death can occur with chest-wall blows in recreational and competitive sports (commotio cordis). Analyses of clinical events suggest that the energy of impact is often not of unusual force, although this has been difficult to quantify. METHODS: Juvenile swine (8 to 25 kg) were anesthetized, placed prone in a sling to receive chest-wall strikes during the vulnerable time window during repolarization for initiation of VF with a baseball propelled at 20 to 70 mph. RESULTS: Impacts at 20 mph did not induce VF; incidence of VF increased incrementally from 7% with 25 mph impacts, to 68% with chest impact at 40 mph, and then diminished at >/=50 mph (p < 0.0001). Peak left ventricular pressure generated by the chest blow was related to the incidence of VF in a similar Gaussian relationship (p < 0.0001). CONCLUSIONS: The energy of impact is an important variable in the generation of VF with chest-wall impacts. Impacts at 40 mph were more likely to produce VF than impacts with greater or lesser velocities, suggesting that the predilection for commotio cordis is related in a complex manner to the precise velocity of chest-wall impact. (+info)