Sports Medicine: Just the Facts

HANDLEBARPOSITION

• Most cyclists select a bar that is just as wide as their
  shoulders, measured as the distance between the shoul-
  der joints. A wider bar opens the chest for better
  breathing and more leverage, but is less aerodynamic.
  You’ll need to find your own balance between the two.
  
  
  1. Handle bar height should always be at or lower
     than seat height. How low depends on the flexibil-
     ity and experience of the rider (Mellion, 1991).
  
  
  
  

CRANKARM

• Length is based on size and riding style. Shorter crank
  arms are better for quick acceleration and high
  cadence. Long crank arms are used for pushing larger
  gears at lower cadence (Colorado).
  
  
  1. To minimize oxygen consumption, crank length is
     dependent on upper thigh (femur) length: 2.33 ×
     (upper thigh length in cm) +55.8 (Too, 1990). This
     roughly translates to the following:
     a. Frame size: <54 cm, 170 mm
     b.55–61 cm, 172.5 mm
     c.≥62 cm, 172.5–175 mm
  
  
  
  

GEARING

EQUIPMENT

• Chain wheels:(1) Large chain wheel (usually 53
  teeth); (2) Small chain wheel (usually 39 teeth)


• Cassette:Clusture of 5–9 gears (cogs) mounted to
  right of rear wheel

GEARRAT I O

• Number of teeth on chain wheel/Number of teeth on
  cog
  
  
  1. Higher gear ratio requires more strength, endurance
     and technique, but yields more power
  
  
  2. Lower gear ratio allows for more spinning and
     higher cadence, and without proper technique may
     yield less power (Mellion, 2001).
  
  
  
  

CADENCE

• Optimal cadence determined by type of race (TT,
  climbing, pack riding), strategies, body type, muscle
  fiber type, training level (Burke, 2002).
  
  
  1. High cadences put less strain on trained cycling leg
     muscles.
  
  
  2. Low cadences increase intramuscular pressure,
     reducing blood flow to the muscles during the
     power phase of the pedal stroke.
  
  
  3. High cadence/low resistance training reduces the
     incidence of overuse injuries. Cyclists beginning a
     season, or returning from injury should attempt
     500–1000 miles of this type of training.
  
  
  4. Cadence is individual, and should be determined
     on a rider to rider basis.
  
  
  
  

INJURIES

GENERAL INJURY DATA

• Approximately 1000 deaths; 23,000 hospital admis-
  sions; 750,000 emergency room (ER) visits, 1.2 million
  physician visits per year (Thompson and Rivara, 2001;
  Hunter, 1998).
  •Bicycle crashes are the second leading cause of sports
  associated serious injury.


• Peak incidence of bicycle related injuries is in the
  9–15-year age group.


• Risk factors for injury: Not wearing a helmet, crashes
  involving motor vehicles, unsafe riding environment,
  and male sex (Thompson and Rivara, 2001).


• Mountain bikes account for 3.7 of overall injuries, but
  51–85% of all mountain bikers sustain injuries each
  year (Kronisch and Pfeiffer, 2002; Gaulrapp, Weber,
  and Rosemeyer, 2001).


• BMX bikers are frequently injured doing stunts; 6.3%
  of all BMX riders sustain injuries in competition
  (Thompson and Rivara, 2001).

TRAUMATIC INJURIES

UPPEREXTREMITY

• Fall on outstretched hand (FOOSH) injuries from
  falling:
  
  
  1. Scaphoid fracture
  
  
  2. Distal radius fracture (Colles fracture)
  
  
  3. Fractures of the radial head
     4.Acromioclavicular(AC) joint separation—usually
     direct trauma to involved shoulder
     a. Initial treatment is sling, with range of motion
     (ROM) exercises as tolerated.
     b.First and second degree may resume riding as
     comfort permits.
     c. Third degree may take 4–6 weeks to heal.
     d. Clavicular fracture
     e. If aligned, may return to riding in 48 h.
     f. Nonaligned may return in 4–6 weeks or as pain
     dictates.
  
  
  
  

HEAD

• Account for most bicycle related deaths (1000/year)


• Generally preventable with helmets (severity reduced
  85–90%) (Thompson and Rivara, 2001; Stephans-
  Stidham and Mallonee, 2001)

SKIN

•Lacerations

• Abrasions (road rash): Graded as first degree (superfi-
  cial), second degree (partial thickness), or third degree
  (full thickness)

482 SECTION 6 • SPORTS-SPECIFIC CONSIDERATIONS