Functional knee brace use for 21 h leads to a longer duration to achieve peak vertical ground reaction forces and the removal of the brace after 17.5 h results in faster loading of the knee joint.

PURPOSE: To investigate the landing strategies used after discontinuing and continuing the use of a functional knee brace (FKB) while performing a drop jump. METHODS: Following published methodology and power analysis, 23 uninjured male athletes, mean age of 19.4 ± 3.0 years, performed seven tests, during three test conditions (nonbraced, braced and removed brace or continued brace use), over 6 days of 12 testing sessions (S) for a total of 38.5 h. Each subject was provided with a custom-fitted FKB. This study focuses on the single leg drop jump kinetics during S12 when subjects were randomly selected to remove the FKB after 17.5 h or continued use of FKB. The time to peak vertical ground reaction forces (PVGRF) and PVGRF were recorded on landing in eight trials. RESULTS: After brace removal, a significantly shorter mean time to PVGRF was recorded (9.4 ± 22.9 msec (3.9%), p = 0.005, 95% confidence interval (95% CI): -168.1, 36.1), while continued brace use required a nonsignificant (n.s.) longer mean duration to achieve PVGRF (19.4 ± 53.6 msec (8.9%), n.s., 95% CI: -49.7, 73.4). No significant mean PVGRF difference was found in brace removal (25.3 ± 65.8 N) and continued brace use (25.1 ± 23.0 N). CONCLUSION: Removal of FKB after 17.5 h of use led to a significantly shorter time to achieve PVGRF, while continued brace use for 21 h required a longer duration to achieve PVGRF, suggesting faster and slower knee joint loading, respectively. Understanding the concerns associated with the use of FKB and the kinetics of the knee joint will assist clinicians in counselling athletes about the risks and benefits of using an FKB. LEVEL OF EVIDENCE: Level II.

Controversies in the medical clearance of recreational scuba divers: updates on asthma, diabetes mellitus, coronary artery disease, and patent foramen ovale.

Primary care and sports medicine physicians are frequently consulted on medical clearance for prospective recreational divers. We discuss four common and controversial medical conditions--asthma, diabetes mellitus, coronary artery disease, and patent foramen ovale--as they relate to fitness to dive. For each condition we review the relevant anatomy and physiology, current recommendations, and the pertinent medical literature. Finally, we offer evidence-based recommendations regarding fitness to dive for potential divers with these conditions.

Asthma and recreational SCUBA diving: a systematic review.

Asthma has traditionally been a contraindication to recreational self-contained underwater breathing apparatus (SCUBA) diving, although large numbers of patients with asthma partake in diving. The purpose of this paper is to review all the research relevant to the issue of the safety of asthma in divers. MEDLINE and MDConsult were searched for papers between 1980-2002. Keywords used for the search were 'asthma', 'SCUBA' and 'diving'. Additional references were reviewed from the bibliographies of received articles.A total of fifteen studies were identified as relevant to the area. These included three surveys of divers with asthma, four case series and eight mechanistic investigations of the effect of diving on pulmonary function. The survey data showed a high prevalence of asthma among recreational SCUBA divers, similar to the prevalence of asthma among the general population. There was some weak evidence for an increase in rates of decompression illness among divers with asthma. In healthy participants, wet hyperbaric chamber and open-water diving led to a decrease in forced vital capacity, forced expired volume over 1.0 second and mid-expiratory flow rates. In participants with asymptomatic respiratory atopy, diving caused a decrease in airway conductivity.There is some indication that asthmatics may be at increased risk of pulmonary barotrauma, but more research is necessary. Decisions regarding diving participation among asthmatics must be made on an individual basis involving the patient through informed, shared decision making.

Alpine ski injuries and their prevention.

Alpine skiing is a popular sport with significant risk of injury. Since the 1970s, injury rates have dropped from approximately 5 to 8 per 1000 skier-days to about 2 to 3 per 1000 skier-days. The nature of the injuries has also been transformed over the same period. Lower leg injuries are becoming less common while the incidence of knee sprains and upper extremity injuries is becoming more common. Much of this change can be attributed to advancements in binding technology, which effectively reduces lower leg injury, but does not adequately address the issue of knee sprains. Along with design, binding adjustment and maintenance are important preventative factors. Poorly adjusted bindings have been correlated with increased injury rates. Upper extremity injuries constitute approximately one-third of skiing injuries, with ulnar collateral ligament sprains and shoulder injuries being the most common. Strategies to prevent these include proper poling technique and avoidance of non-detachable ski pole retention devices. Spinal injuries in skiers have been traditionally much less common than in snowboarders, but this disparity is likely to diminish with the recent trend of incorporating snowboarding moves into skiing. Strategies to help reduce these injuries include promoting the development of terrain parks and focussing on proper technique during such moves. Head injuries have been increasing in incidence over recent decades and account for more than half of skiing-related deaths. The issue of ski helmets remains controversial while evidence for their efficacy remains under debate. There is no evidence to demonstrate that traditional ski instruction reduces injury frequency. More specific programmes focussed on injury prevention techniques are effective. The question of pre-season conditioning to prevent injuries needs further research to demonstrate efficacy.

Topical glyceryl trinitrate for chronic Achilles tendinopathy.

OBJECTIVE: To determine whether continuous application of topical glyceryl trinitrate decreases pain and symptoms in chronic noninsertional Achilles tendinopathy. DESIGN: Randomized double-blind placebo-controlled study of 6-months' duration. SETTING: Community and referral study at an Australian University Hospital. PARTICIPANTS: Recruitment was through newspaper advertisements and private consulting rooms. Eligibility criteria were age >18 years, a history of insidious onset of Achilles tendon pain, a tender nodule localized to the region of the calcaneal insertion, and an ultrasound examination that excluded a tendon tear. Exclusion criteria were Achilles tendinopathy of <3 months' duration, a previous operation on, or dislocation of, the affected ankle or leg, distal neurologic signs, a local corticosteroid injection in the previous 3 months, and current pregnancy. The 65 participants (84 affected tendons; 62% men) had a median age of 49 years (range, 24-79 years), with a median duration of symptoms of 16 months (range, 4-147 months). INTERVENTION: Participants were assigned an active transdermal patch (1/4 of a Nitro-Dur 5 [Schering-Plough] glyceryl trinitrate patch), which delivered 1.25 mg of glyceryl trinitrate over 24 hours, or a placebo patch. Patients were required to cut the patches into quarters and apply 1/d to the site of maximal tenderness for the 24-week duration of the study. All patients were also given 500-mg paracetamol tablets for use with headaches, and instructed in a rehabilitation program that comprised rest from aggravating activities, the use of heel-raise wedges, prolonged daily stretching of the gastrocnemius and soleus musculature, and an eccentric calf muscle-strengthening program. MAIN OUTCOME MEASURES: At the baseline, 2, 6, 12, and 24-week examinations the patient completed a symptom assessment sheet to rate the severity of Achilles pain with activity, at rest, and at night (0 = no pain, 4 = very severe pain). The single assessor used the same scale to measure local tenderness; an 11-point scale for the patient to report pain after the single-leg 10-hop test; and also measured the ankle plantar flexor mean peak force and ankle plantar flexor work. Follow-up was 89% complete. MAIN RESULTS: The groups did not differ in pain with activity, night pain, or local tenderness until the 12-week assessment when participants in the glyceryl trinitrate group reported less pain on each measure (mean scores, 0.9 vs. 1.6 [P = 0.02]; 0.2 vs. 0.7 [P = 0.04]; and 0.9 vs. 1.6 [P = 0.02], respectively). The difference was maintained at 24 weeks for pain with activity (mean scores, 0.4 vs. 1.0 [P = 0.03]). At 24 weeks the glyceryl trinitrate group reported less pain on the 10-hop test than the placebo group (mean scores, 0.5 vs. 1.6 [P = 0.005]). Although the intervention group showed a greater increase in plantar flexor mean total work at 24 weeks than the placebo group, the baseline scores were significantly different. The groups did not differ in pain at rest or in ankle plantar flexor peak force. Combining all the measures showed an estimated 14% (95% CI, 9%-19%) excess of asymptomatic tendons in the intervention group at 6 months. Reported main side effects were headaches (glyceryl trinitrate group, 53%; placebo group, 45%) and rashes (glyceryl trinitrate group, 16%%; placebo group, 12%). CONCLUSION: A topical glyceryl trinitrate patch was more effective than placebo for reducing pain from chronic noninsertional Achilles tendonitis in the first 12 and 24 weeks of use.