Musculoskeletal injures such as muscle strains and tears are extremely common in sports injury. The overall result of muscle injury is not only influence on athlete performance but is also the source of pain. As muscle tightness is one of the predisposing factor for injuries, preventive measure such as stretching exercise have been wildly practiced from amateur players to elite athletes. It becomes an integral part of any sports activity.
Warm-up and cool down exercises are highly recognized as essential parts of any sports activity. The aim of warm-up is designed to increase muscle-tendon suppleness, stimulate blood flow to peripheral, increase temperature of body, muscle tendon and connective tissue; and enhance free, coordinated movement. Examples are jogging, cycling, massage, stretching. Past researchers have investigated the effect of various modes of warm-up, such as jogging, cycling exercise, massage, heat, stretching, isometric contraction and proprioceptive neuromuscular facilitation(PNF).
There are some recommendations by sports scientist:
Static stretching is more recommended than PNF among the techniques. But it is only showed beneficial when multiple intervention is implemented. A study by demonstrated that isometric contraction would produce same relaxation effect as passive stretching. As lengthening of connective tissue occur in both routines. The author also suggested that combination of contraction and stretching is even more effective to promote relaxation. As research findings related to PNF is uncertain, the use of PNF in injury prevention is still controversial.
Most of the literature suggested stretch holding period range from 10 to 30 seconds. Some stated that 30 second or less is recommended. During the stretch one should felt the stretch, but with no pain and within comfortable zone. As pre-disposing injury such as microscopic muscle tears due to over-stretching may contribute to the subsequent muscle injury. Moreover, 12-18 seconds is recommended by since stress relaxation occurs in that period. Other suggested that 15 seconds stretch is as effective as 45 seconds and 2 minutes stretch on hip abduction range.
The first 4 repetition is shown to be most effective . A repetition of 2 to 4 times is also recommended by another author. Other opinions such as 5 to 6 times in improving hip, knee and ankle flexibility are said to be effective.
Specifically for PNF technique contract- relax, literature suggested that one should contract and hold 6-8 seconds, then relax and stretch for other 6-8 seconds. This maneuver should be repeated 3-6 times.
Points of Consideration