According to epidemiological study of weight training-related injuries in US emergency departments from 1090 to 2007, most injuries occurred with free weights (90.4%) with weights dropping on the patient (65.5%). The majority of weight lifting injuries occur among males, adolescents, and older persons. Injuries occur most commonly in the low back and shoulders, consisting mostly of strains and strains (46.1%). (Kerr 2010)
Several risk factors for injury in weight training have been suggested in the scientific literature.
Examples of Potentially Vulnerable Movements
Many Potentially Vulnerable movements have been proposed in the literature.
- Shoulder abduction with external rotation as seen in Behind Neck Presses and Behind Neck Pulldowns (Gross 1993)
- Bench Pressing with hand spacing wider than 1.5 times biacromial width (Fees 1999, Green 2007)
- Rounded back position as seen in Straight Leg Deadlift with spinal articulation (Zatsiorsky & Kraemer 1995)
Also see Controversial Exercises and Over Generalizations. Interestingly, many individuals can apparently perform these movements years on end with little to no repercussions. It appears risk for injury is multifaceted, meaning more than a single factor plays a role in a given weight training injury.
Risser (1990) reported an increased risk of injury with an inadequate warm-up. See exercise specific warm-up for weight training.
Kolber (2010) remarks that weight training routines often emphasize large muscles that produce gains in strength and hypertrophy, subsequently neglecting the smaller muscles responsible for stabilization (such as the rotator cuff and scapular musculature) which predisposes participants to shoulder strength imbalances. This combination of repetitive loading, unfavorable positioning and biased exercise selection creates joint and muscle imbalances, thus may place weight training participants at-risk for injury.
Kolber (2010) identifies shoulder joint and muscle imbalances associated with weight training include:
- Limited internal rotation mobility
- Excessive external rotation mobility
- Occult anterior shoulder instability
- Posterior Shoulder Tightness
- Relative weakness of External Rotators compared to internal rotators or abductors
- Relative weakness of Lower Trapezius compared to abductors
Low back pain has been attributed to mechanical factors, particularly overloading the spine. Low back pain occurs more frequently in people with weak or nonproportionally developed muscles. Issues may include weak abdominal wall and spinal lordosis. (Zatsiorsky & Kraemer 1995)
Overuse / Overtraining
The risk of injury is further exacerbated by overuse brought about by the inappropriate use of advanced weight training techniques or poor workout design. These practices include the constant use of high volume training, chronic use of near maximal workloads, and the practice of advanced techniques such as forced repetitions and negatives (Green 2007). Similarly, Zatsiorsky & Kraemer (1995) recognize the dangerous of a novice attempting to replicate and engage in a more advanced sports conditioning program. Also see Overtraining.
Loss of Form Under Heavy Resistance
Risser (1990) reported an increased risk of injury with loss of form when lifting heavy weights. Kolber (2010) however could not find evidence to support the notion that using heavy weights increased the risk of injury. In fact he found no evidence that individuals who lifted lighter weights and higher reps were less at risk than the individual performing 1 repetition maximum or powerlifting. (Kolber 2010)
Technical performance errors increase the risk of shoulder anterior instability, atraumatic osteolysis of distal clavicle, and Pectoralis Major rupture. In Olympic-style weightlifters, losing control of a heavy load during a weightlifting exercise is the most common mechanism for acute subluxation or dislocation and concurrent instability. Risk of injury has also be attributed to altered proprioception from shoulder instability or past injury (Green 2007).
Lack of Proper Coaching or Supervision
Van der Wall (1999) suggested the high incidence of shoulder injuries reported in weightlifters and bodybuilders may be a consequence of reduced professional supervision, especially at the amateur level.
Anabolic-androgenic steroids (AAS) have been suggested to increase the risk of tendon tears in athletes particularly when combined with rapid increases in training intensity and volume. This is thought to be primarily due to the mechanical stresses encountered from the rapid increases in muscular performance when using these substances (Hoffman & Ratamess 2006, Butt 2015).
Resistance progression can increase dramatically from work out to work out during the start of a cycle or soon after increased dosage. The muscle and accompany structures may also be more susceptible to injury as AAS levels decrease.
Problems with Information
Kolber (2010) warns that the majority of the documented shoulder injuries identified in the literature are from retrospective surveys and descriptive epidemiological reports. Therefore it is difficult to determine with certainty the precise etiological mechanisms of injury in nontraumatic cases, particularly since many of the surveys use an athletic population. This makes it even more difficult to ascertain the true cause of these injuries (ie: sport or weight training). Kolber also warns caution when interpreting injury surveys because there are various levels of participation and not all training programs and designs are of the same intensity and format despite being labeled as weight training.
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