The Prevalence of Fascia Lesions in Muscle Strain Injury

Muscle strain is one of the most common musculoskeletal injuries in sports athletes. Skeletal muscles and their tendons are not the only structures transmitting and bearing loads. Fascia has been demonstrated to have a role in force transmission with a close connection to the muscles. It is commonly assumed that strains in the soft tissue mostly are related to muscles. However, since both muscle and connective tissue are involved in force transmission, both would suffer.

A review was conducted to elucidate the prevalence of connective tissue lesions in muscle strain injury and their potential impact on return-to-play duration. The authors reviewed imaging studies describing the frequency, location, and extent of soft tissue lesions in lower limb muscle strain injuries.

They found 16 studies (fair to good methodological quality) and summarise that the prevalence of strain injury on imaging studies was

• myofascial lesions: 32% (between 24%-40%)
• myotendinous lesions: 68% (between 60%-77%)
• isolated muscular lesions: 13% (between 3%-30%)

The evidence regarding associations between fascial damage and return-to-play duration was not clear.

The results of the study show that lesions of the fascia and the tendinous junction, are highly prevalent in muscle strain injuries.  The location with the highest injury prevalence was the myotendinous junction, which could be due to its role in force-transmitting function during muscular contraction. Almost a third of the injuries affect the epimysium or fascia and its junctions to the muscle. Although fascia can have a high strain tolerance and resistance to elongating forces, it does not have the capacity to quickly and actively react to high external forces. The authors hypothesized that fascia mechanically assists the muscle in taking up loads. When the strain is too high, fascia can also be damaged.