We will cover bicycling injuries when we go on a mountain biking excursion this month. Cases will be presented involving both road cyclists and mountain bikers.
A brief overview follows.
Injuries come in three categories:
1) Acute trauma
2) Overuse injuries
3) Environmental hazards.
I. Trauma
Mountain biking may have a few subgroups that qualify as extreme sport. As extreme sports become more common, it is important to note that practitioners rarely have medical insurance.
Bicycle Injuries are becoming more common in adults. Safety campaigns are directed mostly at children. In Massachussetts, the incidence of accidents was stable for kids in late 90’s but rose by 30% for adults. 51% were unhelmeted, accounting for 75% of closed head injury. 16% had a positive serum alcohol.
California Cycling Club: Reports a 41% yearly injury rate. Of these, most are minor, 26% required medical care. Only 1% required hospitalization. Extremity injuries accounted for 90% injuries. Head and neck trauma occurred in 12%. Victims were helmeted in 88%. Equipment failure accounted for 7% of injuries.
Downhill mountain bike injuries: common mechanism is going over the handlebars. Among racers, women more at risk than men. Injuries to torso and upper extremities. One report of fatality from diaphragmatic rupture.
Road vs. Mountain bike Injury Pattern.
Mountain bikers have a 40% - 60% decreased incidence of head/face/dental injuries than roadies. Mountain bikers are also less likely to be hospitalized, less likely to have severe injuries. These findings are because of decreased traffic on mountain trails and increased helmet use among mountain bikers.
So it is safer with helmets and safer off road!
A JAMA study showed that helmets provide 4-fold protective effect against head injury. Helmets are 85% effective against head injury and 88% effective against brain injury.
Helmet type does not matter. Hard shell, thin shell (most), and no shell helmets are all equally effective. All must meet ANSI, Snell requirements. Fit is probably the most important consideration when buying a helmet.
Helmets reduce risk of nose and upper face injury by 65%. California helmet legislation has resulted in 18% reduction in head injury for<18 yrs.
II. Overuse injuries.
1. De Quervain’s Disease. Overuse injury of thumb tendon. Repetitive shifting. Pain on inside of wrist and thumb movement.
2. Patellofemoral pain. Overworking the quadriceps. Using too high gears. Hill training.
3. Low Back Pain. Very Common. Fit of bicycle is important.
4. Ulnar tunnel syndrome. Bilateral ulnar distribution numbness. Treat with rest splinting, and NSAIDs.
5. Cyclists palsy. Distal ulnar nerve sensory and motor dysfunction. 92% IN A SERIES OF 25 cyclists completeing 600 km ride. No significant difference on mtn vs road handlebars for motor symptoms, Sensory sx more common in mtn bike group. Gloves, bicycle fit, changing hand positions also important.
6. Scrotal abnormalities. Microlithiasis, Spermatocele. Hydrocele, Scrotoliths, Varicoceles. More common in Biker group.
7. Bilateral Pudendal nerve injury secondary to excessive biking has been reported. ED may develop. However, Bicyclists have no more ED than runners and less ED than the general pop, reflecting healthier subpopulation. Authors recommend comfortable saddles and rear suspension on bikes.
Possible benefit. Mountain bikers have increased bone density and protection from osteoporosis compared to road cyclists.
III. Environmental Injuries
1. Hypothermia. This is rarer than hyperthermia, but can occur with rapidly changing weather conditions.
2. Hyperthermia. A real risk in the desert
3. Hyponatremia. Low serum sodium occurs when salt loss through sweating is accomanied by hypotonic fluid intake - like drinking water without salt-containing foods.
4. Lightning Injury. A real risk in summer afternoons. Lightning is the subject of another lecture.
5. Cactus injury
6. Animal encounters. Bites will be covered separately. Look for upcoming posts!
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