Sometimes referred to as a pulled muscle, is a muscle injury that causes fibers to tear within the tissue. Muscle strains are produced by excessive tensile stress. A muscle strain generally does not result from excess stretch alone, but from a combination of tension and contraction. Due to muscle mechanics, strains are more likely when the muscle is in eccentric contraction (lengthen) rather than concentric (shorten) or isometric (no change). The muscles most susceptible to strain injuries are multiarticulate muscles, which are those that cross more than one joint. The more joints crossed by a muscle, the greater their vulnerability for strain injury. All involved joints cannot achieve full range of motion at the same time due to limited extensibility of the muscle‐tendon unit. If the muscle is stretched across multiple joints, it is susceptible to tearing from excess tensile stress. Strains can develop in any part of the muscle, but ordinarily occur at the musculotendinous junction. The junction of muscle and tendon places one tissue with higher pliability (muscle) directly adjacent to another with limited pliability and more tensile strength (tendon). As a consequence, the point of interface between the two tissues becomes a site of mechanical weakness; this is where strains often occur.
There are three grades of muscle strain: first degree or mild, second degree or moderate, and third degree or severe. In a first‐degree strain, few muscle fibers are torn. There may be some post‐injury soreness, but the individual usually returns to normal activity levels quickly. With second‐degree strains more fibers are involved. There is a greater level of pain and a clear region of maximum tenderness in the muscle tissue. Soft tissue manipulation is extremely helpful in the recovery process for first and second degree strains.
A complete rupture of the muscle‐tendon unit occurs with a grade three strain. Because of extensive damage, strains are sometimes classified as third degree even though the muscle still has a few fibers intact. Significant pain is likely at the time of injury. Pain can be minimal afterwards, because the ends of the muscle are separated and limb movement does not cause additional tensile stress. Third‐degree strains generally require surgical repair. In some instances, surgery is not performed because the muscle does not play a crucial role and the potential dangers of surgery outweigh the benefits. Ruptures to the rectus femoris are an example because the other three quadriceps muscles make up for the strength deficit caused by the strain.
As Bodyworkers & Functional Movement Therapists we focus on balancing the muscle and fascial systems of the body to improve range of motion, posture, and support pain free living. We are able to view your muscle imbalances and Design the best treatment plan specific to your needs and properly address your muscle strains and pain.