Muscular Injury

Muscular injury is one of the major problems facing today’s athletes, both recreational and professional. Injuries to skeletal muscle represent 30% of the injuries seen in sports medicine clinics. As a result, it is imperative to utilize the most effective means to aid in deterring these injuries. Two terms that often seem synonymous are ‘warm-up’ and ‘stretching’. Is there a difference? Is one better than the other, and when? In this article, we’ll take a deeper look into both.

Warm-up is intended to perform the following two major functions: (1) improve a muscle’s dynamics so that it is less inclined to injury; and (2) prepare the athlete for the demands of exercise. Warm-up can be either passive or active. A passive warm-up is one in which muscle temperature or core body temperature is increased by external means. This can include, for example, hot showers, saunas, or heating pads. Active
warm-up involves some type of physical activity. These can be general warm-ups, which involve any non-specific body movements such as jogging, cycling, or calisthenics. Or these can be specific warm-ups which utilize activities and stretches that are specific to the sport for which one is preparing. The most effective of the warm-up techniques appears to be the specific warm-up, possibly since it mimics the activity to be performed.

The intensity of the warm-up should be tailored to meet the needs and abilities of each individual. For example, a poorly conditioned athlete will not require the same intensity or duration of warm-ups as the well-conditioned athlete to achieve the same elevation in muscle temperature. It has been reported that a warm-up provides a protective mechanism to muscle by requiring a greater length of stretch and force to produce a tear in the warmed muscle.

Two major types of stretching are dynamic and static. The dynamic stretching technique involves the use of bouncing or jerking-type motions to stretch a muscle group. An example is using a bouncing method downward to touch the toes. Static stretching is often referred to as slow or passive stretching. In this method, a slow, deliberate movement is used to achieve a lengthening of the muscle. Typically, each stretch is held for approximately 30 seconds to facilitate connective tissue plastic elongation. It has been found that long-term (non-acute) stretching programs can lead to an increase in flexibility, or the range of motion available for a particular joint. This is important when considering the potential benefits of stretching on muscular injury. For example, ability to lengthen without damage may allow athletes to assume unusual positions that would otherwise result in injury.

Connective tissue flexibility has two components when lengthening: elastic and plastic (non-recoiling) stretching. The amount of plastic stretch determines the amount of permanent lengthening for the connective tissue. Also, it is reported that the most effective lengthening for connective tissue occurs when a ‘lower force of longer duration’ is applied to a tissue with an elevated temperature. Additionally, that this increase in muscle length was maintained for at least 24 hours, with the greatest increases being
maintained during the first 15 minutes immediately following the stretching protocol. As a result, it is suggested that stretching should occur within 15 minutes immediately preceding an activity to have the optimal lengthening benefit of the stretch. Thus, and possibly contrary to what we’ve been told, a quick stretch after a warm-up may be optimum for the athlete.

Injuries occur at certain lengths because of an eccentric force stretching the muscle beyond its ‘free range of motion’ to the point of failure. All physical activities can be thought of in terms of requiring a specific range of motion to carry out the activity. To successfully complete an activity without injury, the muscle must have the ‘stretchability’ necessary to move through that range without causing an increased tension/stress or load on the muscle. It can be theorized that this increase in the length of muscle (optimum length of the muscle) can allow the muscle to move through a greater range of motion, or stretch, before reaching the point of failure.

In conclusion, to best prevent injury to muscles, a strategic routine of warm-ups and stretches are suggested. A daily stretching routine of static stretches with 30-second holds for 3x repetitions can provide a lasting increase of range of motion. Lastly, for athletics, it is best practice to participate in a similar pre-game routine at half-time, for best results in the second half.