Exercise Adaptation / Injury Prevention Tidbits

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Dealing with Injury

Dumbbell Seated Shoulder External RotationImmediately stop an exercise that causes the joint or muscle unusual pain. Do not test or stretch the muscle since further damage could occur. Regardless of the findings the initial treatment remains the same. Administer first aid. Allow time for the joint or muscle to heal as you continue to workout using exercises that do not further aggravate the injury during its recovery. After sufficient recovery time, start back very conservatively with a single set or brief bout with very light resistance. Continue to slowly progress steadily, increasing the load or volume throughout the following weeks, only if you can perform the load pain free. Be cautious not to aggravate the injury by attempting to progress too rapidly. Be aware that it is possible to not feel pain or discomfort after over doing it until after the workout or the next day - after it is too late. See a physician for serious injuries or if the pain persists or gets worse. A sports medicine physician specializes in exercise and athletic related injuries. A physical therapist should also be able to refer you to a physician knowledgeable in exercise related injuries for proper diagnosis. A specialist can help you determine possible underlying causes of the injury and make necessary program modifications to prevent future injuries. See Adaptation Criteria and Causes of Injury.


Injury Rehabilitation Phases

  1. Immobilization
  2. Range of motion (ROM)
  3. Strength
  4. Return to activity

Bomgardner R (2001) Rehabilitation phases and program design for the injured athlete. Strength and Conditioning Journal, 23(6): 24-25.

  • Inflammation Phase
    • First aid and Immobilization
    • Manage inflammation
    • Lasts days
  • Repair Phase
    • Rehabilitative exercises
    • Fibroplasia (formation of collagen)
    • Angiogenesis (formation of new local blood vessels)
    • Lasts weeks
  • Remodeling Phase
    • Conservative reintroduction of activity
      • progressive increases of intensity and volume
    • Collagen maturation and remodeling initiate
    • Lasts months

Evans P (1980). The healing process at cellular level: a review. Physiotherapy, 66(8): 256-259


Irritability Scale

Irritability can be rated Low, Medium, or High based on 3 factors:

  • Pain level (Score of 1-10)
  • What it takes to provoke the symptoms
  • Latency or time it takes the symptoms to resolve after provocation

Care must be taken when assessing patients of high irritability because once symptoms are provoked, the remaining assessments are unclear.

Tovin BJ (2006). Prevention and Treatment of Swimmer's Shoulder. North American Journal of Sports Physical Therapy, 1(4): 166-175.


Strength Imbalance and Injury Relationship

Individuals with strength differences of more than 10% between the quadriceps of the right and left legs were more likely to sustain lower limb injuries compared to individuals without such strength imbalances (Bender et al, 1964).

If these strength differences were due to past injury, one could speculate that previous injury at least partly attributed to increased the risk of injury, not necessarily the strength imbalance itself, since past injury is most predictive of future injury (see studies below) and past injury typically results in weakness (and decreased range of motion) in the injured limb.


Ankle Sprain Predictors

BMI and past ankle sprains were much more predictive of future injury in high school athletes than were balance, height, ligamentous laxity, ankle tape/bracing usage, and hip strength balance. High school football players were 16 times more likely to sustain an ankle sprain if the athlete was overweight or obese and had a history of ankle sprain. Incidentally, the use of preventive taping or bracing did not reduce the incidence of injury.

Mirabella MR, Tyler TF & McHugh MP (2004) Risk Factors for Ankle Sprains in High School Football Players. Journal of Athletic Training. Supplement 39(2), 38.

Tyler TF, McHugh MP & Tetro (2004) Risk Factors for Ankle Sprains in High School Athletes. Journal of Athletic Training. Supplement 39(2), 37.


Exercise & Arthritis

Exercise can decrease pain and improve functional capacity, ROM, and muscular strength

Felson DT, Lawrence RC, Hochberg MC, McAlindon T, Dieppe PA, Minor MA, Osteoarthritis: New insights. Part 2. Treatment approaches. Ann Intern Med. 133:726-737, 2000.

Casper JM, Berg K. Effects of exercise on osteoarthritis: A review. J Strength Cond Res. 12:120-125, 1998.


Foot Parts

The human foot has 26 bones, approximately 20 muscles, 33 joints, and over 100 ligaments holding it all together.


Connective Tissue Sheaths

Weight training may strengthen the sheaths of connective tissue within and around the muscle by increasing their collagen content. These connective tissues sheaths provide the framework that supports muscle overload and are the main component in the tensile strength and passive viscoclastic properties of muscle.

    • endomysium surrounds individual fibers
    • perimysium encloses groups of muscle fibers
    • epimysium surrounds the entire muscle

Pectoralis Tear

Fewer than 200 cases of total or near-total pectoralis ruptures have been reported in the literature (Aarimaa 2004).

The first incidence of those 200 cases was described by Patissier in 1866 documenting a French boy who tore his pectoral tendon while he was lifting an heavy piece of beef from a hook. Later in 1861 Letenneur reported a similar case. (Merolla 2012)

Aarimaa VJ, Rantanen J, Heikkila, Helttula L, Orava S (2004). Rupture of the pectoralis major muscle. Am. J. Sports Med. 32:1256–1262.

Merolla G, Paladini P, Campi F, Porcellini G (2012). Pectoralis major tendon rupture. Surgical procedures review. Muscles Ligaments Tendons J. 2012 2(2):96-103.


Bone

Tensile strength and elasticity of bones decrease about 2% per decade from age 20 to 90 years (Hayes, 1986).

Bone is only one fifth the weight of steel but can withstand two times the compression force as granite, or four times the compression force as concrete.

Weight bearing activities such as walking can prevent bone mineral loss. Weight resistive exercises can prevent bone mineral loss if the antigravity musculature is activated.

In animal studies, the first 40 repetitions of an exercise stimulate greater than 95% of bone formation. Additional repetitions do not significantly increase bone formation (Riewald 2004).

Astronauts have about the same rate of bone loss as those on bed rest: about one percent per month.

Riewald S (2004). Bone of Contention: What Exercises Increase Bone Strength? Strength and Conditioning Journal. 26(1): 46-47.


Joint Cartilage

Resistance training can thicken the hyaline cartilage on the articular surfaces of the bone (Ingelmark & Elsholm 1948).

Joint cartilage depends on synovial fluid for its nutrition since it has no vascularization. Synovial fluid is forced into the cartilage surfaces when the joint is loaded, as in physical activity. Joint cartilage functions in an elastic manner during short term loading. The cartilage becomes temporarily deformed when long term loading forces water out of the cartilage. It returns to its original shape after cessation of loading when water is again drawn into the cartilage. The alternate compression and decompression along with the pumping of synovial fluid due to physical activity is partly responsible for nutrition to the cartilage.


Tendon and Ligament

Resistance training can increase the size and strength of tendons and ligaments (Fahey et al. 1975). This may be due to an increase of collagen within the connective tissue sheaths (Laurent 1978).

The elastic limit of a tendon or ligament can be enhanced by exercise and training and can be reduced by aging and inactivity. The elastic limits of ligament are estimated to be 12-50%, and the elastic limits of tendon is 9-30% (Weakest at MTJ).

Research using animal models demonstrate that junction strength of ligaments increases with endurance-type physical activity and decreases with immobilization. Furthermore, damaged ligaments regain strength faster if physical activity is performed afterwards.

Junction strength failure of a bone-ligament preparation occurs at the attachment site of the ligament. The Junction strength failure is similar in a bone-tendon-muscle-tendon-bone preparation, although separation may also occur at the muscletendinous junction or in the muscle itself.

Tendons exhibit viscoelastic properties and are adaptive to conditions of increased loading and disuse. Strains within the tendons near their insertion site do not appear to be uniform. The traditional concept of tensile failure may not be the essential factor in the pathomechanics of insertional tendinopathy. Particular joint positions are more likely to stress the area of the tendon usually affected by tendinopathy. Incorporating different joint position during exercise may allow for more controlled stresses on these affected areas of the tendon which may allow for better maintenance of the mechanical strength of that tendon region in effort to prevent injury. Such exercises could stress a healing area of the tendon in a controlled manner thereby stimulating healing once an injury has occurred. (Maganaris 2004)

Fahey TD, Akka L, Rolph R (1975). Body composition and Vo2max of exceptional weight-trained athletes. J Appl Physiol. 39(4):559-61.

Laurent GJ, Sparrow MP, Bates PC, Millward DJ (1978). Turnover of muscle protein in the fowl. Collagen content and turnover in cardiac and skeletal muscles of the adult fowl and the changes during stretch-induced growth. Biochem J. 176(2):419-27.

Maganaris CN, Narici MV, Almekinders LC, Maffulli N (2004). Biomechanics and pathophysiology of overuse tendon injuries: ideas on insertional tendinopathy. Sports Med. 34(14):1005-17.

Also see Ligament Elasticity comment.


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