Both extrinsic and intrinsic factors can increase the risk of injury. Intrinsic factors include biomechanical deficiencies, including malignancy of limbs, muscular imbalances, degenerative processes, and other anatomical factors. Extrinsic factors include training errors, faulty technique, poor environmental conditions, incorrect equipment and surfaces. (Crown 1997).
Extrinsic Factors of injury can be further classified into overuse, misuse, abuse, or disuse (Wanivenhaus 2012).
- Overuse is performing a task with a frequency that does not allow the tissues to recover and symptoms may be due to lack of muscle strength or endurance
- Misuse using improper form or equipment which may put abnormal stress on tissue structures.
- Abuse is having excessive force going though normal tissues.
- Disuse occurs after taking a period of time off without training resulting in deconditioning or altered neuromuscular control
Excessive fatigue can negatively affect proper form and/or decreases the ability of stabilizers to maintain sound biomechanics. Careful monitoring of training volume, intensity, and duration will minimize overuse injuries. (Wanivenhaus 2012)
Intrinsic factors such as stability and mobility defiencies have been attributed to athletic and fitness related injuries. Compensatory movement patterns develop to overcome stability and mobility deficiencies. These poor movement patterns are used subconsciously whenever executing future tasks leading to greater mobility and stability imbalances and deficiencies which increase risk of injury. (Cook 2010)
Prior injury is one of the the most significant risk factors predisposing individuals to injuries. A decrease in proprioceptive input occures if an injury is left untreated or inappropriately treated. A disruption in proprioception will negatively effect movement-pattern behaviors. The altered mobility, stability, and asymmetric influences eventually lead to compensatory movement patterns, increasing risk of injury. (Cook 2010)
Risk of injury is increased under following conditions:
- Insufficient warm up
- Insufficient recovery
- Training stimulus is not progressive and regular
- Mechanical impairments
Also see first 4 of 5 Adaptation Criteria.
Biomechanical impairments may contribute to orthopedic injury when combined with other factors than may negatively affect joint integrity (e.g. hyper-mobility, biostructural weakness, insufficient adaptation of joint or muscular structures, fatigue, acute or chronic overtraining, etc.). For example, hypermobility does not produce joint instability unless the secondary stabilizers do not function adequately and symptoms occur (Tovin 2008).
The biomechanical impairments are listed for precautionary measures only, so they may be identified and possibly corrected in attempt to decrease risk of athletic injuries during exercise or physical activity. These impairments are possible risk factors for injury and may only increase injury when combined with other risk factors. A physician may need to establish if a biomechanical deficiency is structural, muscular, neuromuscular, or due to some other pathology.
The corrective exercises assume impairments are due to a muscular imbalance (flexibility, strength, or posture). Only a qualified physician or health care provider should diagnose and give prescription for an existing injury. In some circumstances, an attempt to correct a biomechanical impairment may irritate the injury and prolong recovery, particularly if certain therapy exercises are used inappropriately or initiated too soon or aggressively after an injury has occurred. The exercise selection should be based on positions that do not overstress the healing tissues. Even after an underlying biomechanical impairments have been improved, a preexisting injury may require the attention of a physical therapist under the advice of a physician to restore total functionality. See Injury Prevention Tidbits and Sports Injury First Aid.
In athletic conditioning, improper planning and inadequate conditioning (both general and sports specific) prior to the competitive season are major causes of injury. In elite athletes, high volume and intensity of the training load is one of the major causes of injury (Slobounov SM 2008). Also see Causes of Injury (above).
An improperly planned conditioning program can be attributed to failure to understand and implement fundamental training principles and adaptation criteria through a periodized programming. A program that does not adequately prepare the athlete for the specific types of forces and stresses experienced on the field or court place athletes at risk. See Training Specificity and Resistance Training for the Reduction of Sports Injury. Programs that fail to incorporate movements that condition stabilizing muscles (joint stabilizers such as hamstrings, rotator cuff muscles, etc), maintain ideal muscular balance, and correct biomechanical deficiencies unique to each athlete, increase the risk of injury on and off the playing field.
Contrary to popular belief, conventional stretching per se does not appear to decrease the occurrence of injury (see Stretching and Flexibility). However, movement specific warmups before drills, tests, and the event performance can decrease risk of injury. Ideally, movement specific warm-ups should proceed the event by several minutes, mimic the sports activity in the exact mechanics in which it will be performed, yet, not be so taxing as to compromise sports performance. Some sports are obviously more unpredictable than others and will not allow for rehearsal of every possible movement several minutes before they occur. Power or speed sports should consist a short series of movement specific warmups at progressive intensities. For example, several minutes before the start of 100m dash, a sprinter could perform a short progressive submax series of block starts immediately, followed by a short run, or simulated movement, thereby warming up in the same mechanics in which they will be engaging.
In the weight room, performing a movement specific warm-up set (eg: 50% 10RM) before workout sets, allow for performance benefits in addition to decreasing the risk of injury (see Weight Training Warm-up). Injuries can also be circumvented by well thought-out programs that adhere to evidence based research and sound training protocols (see Weight Training Periodizaiton) that allow for adequate recovery (see Overtraining). Also, using too much resistance or performing too many sets, particularly when athletes are first introduced to new movements or exercise variations are common training errors which can greatly increase the risk of injury.
The coach can introduce methods in which athletes can customized a 'group program' to each athlete's unique abilities, results, and needs. Coaches must allow for proper rehearsal and adaptation to 'new' exercises or movements, understand the benefits periodization techniques, adhere to adaptation criteria, implement program customization, use of movement specific -ups, and schedule adequate recovery periods for optimal progress.
Cook G (2010) Movement: Functional Movement Systems, pg 65-67.
Crown LA, Hizon JW, Rodney WM, (1997) Musculoskeletal Injuries in Sports, The Team Physician's Handbook, Mosby, 2: 361-370.
Slobounov SM (2008). Injuries in Athletics, Causes and Consequences, Springer, 25-43.
Tovin BJ (2006). Prevention and Treatment of Swimmer's Shoulder. North American Journal of Sports Physical Therapy, 1(4): 166-175.
Wanivenhaus F, Fox AJS, Chaudhury S, Rodeo SA (2012). Epidemiology of Injuries and Prevention Strategies in Competitive Swimmers. Sports Health. May 2012; 4(3): 246–251.
- Weight Training Injury Risk Factors
- Weight Training Safety Tidbits
- Training Mistakes
- Swim Injuries
- Effects of Frequency and Duration of Running on Improvements of Fitness and Incidence of Injury