Pnf With A Form Of Static Stretching example essay topic

The American College of Sports Medicine defined fitness in 1990 by stating that physical fitness is "a set of attributes that people have or achieve". (Cited in Dalgleish et al 2001) This set of attributes can be further defined as cardiovascular fitness, muscular endurance, muscle strength, muscle endurance, motor skills and flexibility. Cardiovascular fitness involves the heart and lungs supplying the required volume of oxygen to the working muscles. Muscular endurance is the number of contractions or the length of time a muscle can contract before fatigue occurs. Muscle strength is the maximum amount of force a muscle can generate in one contraction. Motor skills is a general term, which covers co-ordination, speed, balance and power.

Flexibility is the range of motion (ROM) in a joint or in a series of joints. Flexibility is improved by stretching connective tissues, muscles and other soft tissue around a joint. Stretching exercises can be divided into different categories depending on the way the muscles and surrounding tissues are stretched. These forms of stretching are static stretching, dynamic stretching, ballistic stretching and proprioceptive neuromuscular facilitation (PNF). This report will define why athletes stretch and review current literature on each form of stretching and conclude from research which form is the most effective form of stretching. BENEFITS OF STRETCHING Stretching in sport was only used to warm athletes up before an event and cool them down after the event.

Stretching was not used as a part of an athletes training programme until the benefits of stretching were recognised. Sigerseth (1971 cited in Elliot & Mester 1999) suggested that skilled performances could be improved by increasing the ROM around various joints. Performance can be improved due to stretching in three ways. If range of motion is increased especially in throwing and racquet sports, more force or velocity can be produced. This is possible as this increases in ROM allows the throwing distance to increase and longer period of time in which force can be produced. This results in the speed of the racquet, bat or object being increased, which allows a more powerful, throw, kick or hit to occur.

Examples of sports where this occurs is tennis, cricket, baseball and golf. Jobe and Moines (1986 cited in Elliot and Mester 1999) Studied golfers and found that the higher skilled golfers had twice the range of trunk rotation compared to golfers of lesser skill. Athletes who compete in sports where performance is judged on the aesthetics of their performance will benefit from a long term stretching programme. If an athlete has a greater ROM, compared to another athlete, they can place themselves in a position or perform a more complex movement, which will denote a higher technical value, which will result on a higher score being awarded. A stretched muscle can produce a greater contractile force compared to a muscle, which is not stretched. Rapid stretching then releasing it as it is shortened due to the muscle briefly storing the tension develops this.

As it stretches it has the potential to quickly return to its original length. Through flexibility training the elasticity of the muscles can be improved which will increase the contractile force produced. Athletes who need explosive power will benefit from this. Stretching is used during a warm up and cool down. This is done, as people believe that poor flexibility can lead to injury. This can be muscular, joint or connective tissue.

Increasing flexibility in a warm up should decrease the risk of injury. Stretching in a cool down is performed to reduce the delayed onset of muscular soreness (DOMS). This can occur immediately after exercise or up to twenty four hours after exercise. DOMS can last for a few hours to up to several days in severe cases. This may inhibit an athlete training schedule or prevent them from performing. As stretching is used as part of an athletes general training programme and performed during cool downs and warm ups it is essential when evaluating what is the most effective form of stretching to split these categories.

The most effective form of stretching may not be the same for each case. As stretching is performed for different reasons in these situations the most effective form of stretching to increase flexibility will be examined first, then the most effective form of stretching for a cool down and warm up will be examined. The forms of stretching will be described and research on this field of study will be reviewed. Static stretching is when a muscle and surrounding tissues is stretched slowly. Once the muscle is stretched, almost to the point of resistance, the position is held. When the muscle is held in this position the tension decreases and the muscle can be stretched further.

STRETCHING TO INCREASE FLEXIBILITY Static stretching "is not only the safest but also has been test proven for centuries by of Hatha yoga as a means of enhancing flexibility". (Alter 1990 p 11) Similarly "it is difficult to find any good reason why static stretching should not make up the majority of any worthwhile flexibility programme". (Elliot 1998 p 261) Other advantages of static stretching are that it is the easiest to learn and perform. Low amounts of energy are expended compared to other forms of stretching and adequate time is provided to reset the stretch reflex. Static stretching allows a change in muscle length and provides relaxation to the muscle.

Although static stretching is safe and effective it has a major disadvantage. This is the lack of sports specify. The S.A.I. D (Wallis and Logan 1964 cited in Alter 1990) principle suggest that an athlete should stretch at more than seventy five percent of maximum velocity through the same plane of motion, and the same joint angle that will be used when performing in their sport. Static stretching fails to do this. Another drawback is that static stretching does not develop co-ordination or proprioception. A study by Rosenbaum and Henning (1995 cited in Alter 1990) reported it was advisable not to perform only static stretching as this could result in muscle performance being potentially impaired.

The research also concluded static stretching had a decreased force production Dynamic stretching is when the full ROM of a joint is used at fast to very fast speeds. This movement is controlled and does not involve bouncing or jerking of the joint. This form of stretching can be very sport specific. Following the S.A.I. D principles dynamic stretching is the most effective form of stretching, as it is the most sports specific. Muscle has two receptors, which measure speed of contraction and muscle length. Dynamic stretching is the form of stretching those conditions these two receptors for optimal response.

'A series of stretching exercises in which the velocity and range of lengthening are combined and controlled on a progressive basis' (Zachazewski cited in Alter 1990 p 228). This progressive programme lets the muscle and junction to adapt to functional movements. Ballistic stretching is similar to dynamic stretching but it is done faster and momentum from body weight or a limb is used to forcibly elongate the muscle. There are bouncing and bobbing movements in ballistic stretching. As some sports are ballistic in nature ballistic stretching has some support due to being sports specific. There are many crit isms of this form of stretching.

The tissues have inadequate time to adapt to the stretch; this can result in muscle soreness. Ballistic stretching has a high velocity; this causes muscular tension as the stretch reflex is involved. This tension can lead to injury. The speed of the stretch does not allow adequate time for neurological adoptions to occur which will limit flexibility. DeVries (1962 cited in Elliot 1999) compared ballistic and static stretching.

He found that both forms produced significant increases in flexibility but neither form produced better results than the other. DeVries also found that static had three main advantages over ballistic. Theses were lower energy requirements, reduction in muscle soreness (ballistic increased) and less injury risk, as the tissues were not overstretched. Beaulieu (1981) believes twice the amount of tension is created by ballistic stretching compared to static stretching. This potentially means there is twice the risk of injury. Proprioceptive neuromuscular facilitation (PNF) involves performing an isometric (muscle contracts but there is no change in length or movement occurring) contraction before the muscle is stretched.

This allows the muscle to be stretched further than it would be able to alone. The muscle relaxes more after the isometric contraction and is thought to be easier to elongate. Like stretching PNF has many forms. The most popular form is known as the contract-relax-contract (CRC) technique. For PNF stretching a partner is required.

During a CRC stretch the muscle is lengthened, the athlete then isometrically contracts against the resistance provided by their partner. This is followed by a short relaxation period. The athlete then stretches the muscle aided by their partner putting light pressure, which allows an increase in ROM. The advantages of PNF are that it helps to establish a pattern of co-ordinated motion. It uses important neuro psychological mechanisms such as reciprocal innervation and inverse myo tactic reflex. Alter 1990 believes "PNF seems to be the most successful method for developing flexibility" (Alter 1990 p 16).

The disadvantages of PNF are that a partner is required. PNF carries a risk of injury to the muscle itself and can lead to cardiovascular complications. Studies that compare the effectiveness of the forms of stretching are abundant. In the majority of studies ballistic stretching is not involved. This could be construed that ballistic stretching is omitted, as it is the least effective form of stretching. Lucas and Kos low (1984 cited in McAtlee 1993) studied 63 collage women over seven weeks they examined the effects of static, dynamic and PNF stretching techniques on the hamstring and muscles.

All three were found to produce significant improvements with no real difference in results. Dynamic stretching produced slightly improved results. They concluded that stretching time might influence effectiveness. They reviewed other studies and found in short treatment time (12-18 mind) PNF produced highest improvements compared to studies over medium (their study) and long treatment times which produced no difference between stretching types. Condon and Hutton (1987 cited in McAtee 1993) compared three PNF techniques for increasing flexibility of the ankle joint with passive stretching (form of static). They found no difference between techniques.

Mei dors et al (1977 cited in McAtee 1993) compared static, PNF and dynamic stretching and found no difference in gains. Although these studies offer little evidence for one form of stretching being more effective that the others studies that pinpoint one form over the others have been produced. Tanigawa (1972) compared PNF with a form of static stretching on hamstring flexibility. He studied thirty normal males with tight hamstrings He found that PNF increased flexibility more than static stretching. Moore and Hutton (1980 cited in McAtlee 1993) used electromyography to investigate the difference between static stretching and PNF.

Their results provided evidence that PNF increases flexibility more than static stretching. Say et al (1982 cited in McAtlee 1993) compared the four forms of stretching on shoulder, trunk and hamstring flexibility. They found PNF increased flexibility greatly compared to the others. Studies by Prentice, (1983 cited in McAtlee 1993) and Cornelius and Crafthamm (1988 cited in McAtlee 1993) also show PNF stretching to produce the best improvements in flexibility.

McAtlee (1993) researched fourteen studies and found eight of these studies showed PNF as the most effective form of stretching. PNF carries a potential risk of injury. Moore and Hutton (1980 cited in McAtee 1993) found that isometric contraction before the stretch results in a higher reading. This potentially puts the muscle at risk during the stretch. Due to the isometric contraction blood pressure can momentary increase.

Cornelius and Crafthamm (1988 cited in McAtlee 1993) that this increase in blood pressure produces no risk to the healthy individual. This could cause problems for individuals who already suffer from high blood pressure. STRETCHING AS PART OF A WARM UP OR COOL DOWN As mentioned earlier stretching is used as part of a warm up and cool down. This is done to gradually increase / decrease the body temperate, prevent injuries and reduce DOMS.

The most important aspects is preventing injury and reducing muscle soreness. The most effective form of stretching would be the form that provides the highest injury prevention and reduces muscle soreness the most. Recent studies on stretching preventing injury have shown that stretching does not prevent injury or significantly reduce DOMS. Walker (2003 cited in Peak Performance issue 2003) reviewed five studies on the effects of stretching on DOMS before and after stretching. They found in the following seventy four hours after exercise stretching only reduces DOMS by two percent.

The Australian Army on one thousand and ninety three male recruits conducted a study on stretching and injury risks. The results were published in the Australian Journal of Physiotherapy 1998. Recruits were split into a control group and a stretching group. Recruits in the stretching group stretched their calf muscles during their warm-ups, while control-group subjects did not. At the end of the study, the total frequency of five different types of lower-leg injury in the stretch group was 4.2 per cent, compared with 4.6 per cent for the control group. Another study on stretching and injury was conducted on one thousand five hundred and thirty eight Australian Army recruits.

The results were published in Medicine and Science in Sports and Exercise 2000. The recruits were divided into a control group and a stretch group. The control group carried out a warm-up of jogging and side-stepping but completed no stretching. The stretching group performed stretches after the warm up on the major muscles of the lower limbs. Over the duration of this study there were one hundred and seventy five lower limb injuries in the control group and one hundred and fifty eight in the stretching group.

Although the injuries occurred in the control group was higher than the stretching group confirmed that this is not a significant difference. CONCLUSIONS Due to the two studies on the Australian Army the most effective form of stretching for a warm up and cool down is irrelevant as stretching is not significantly effective in warming up and cooling down. The research on comparisons of stretching forms has shown that PNF stretching is the most effective form of stretching to increase flexibility. Static stretching and dynamic stretching are slightly less effective but do not have as many risks as PNF. Dynamic stretching is the most sport specific.

After discovering these facts I would recommend that athletes perform dynamic stretches as their flexibility training programme. Stretching during a warm up and cool down has been shown to produce minimal results, however if an athlete would like to stretch during these periods I would recommend dynamic stretching as it is very sport specific. Ballistic stretching is not recommended and PNF stretching should only be performed by athletes who are knowledgeable on the subject with assistance from partners who also are knowledgeable on PNF. REFERENCE SAlter M. J 1990 Sport Stretch 2nd ed Human Kinetics Australian Army 2000 'A randomized trial of pre-exercise stretching for prevention of lower limb injury' Medicine and Sport in Science and Exercise vol 32 (2) p 271-277 Australian Army 1998 'Effects of flexibility and stretching on injury risk in army recruits' Australian journal of Physiotherapy vol 44 p 165-172 Boyle PM 2004 'The effects of static and dynamic stretching on muscle force production' Journal of Sports Science vs. 22 i 3 p 272-273 Elliott B, Mester J 1998 Training in sport John Wiley & Sons Ltd Fletcher IM, Jones B 2004'The effects of different warm up protocols on 20 meter sprint performance in trained rugby union players' Journal of Strength and Conditioning vs. 18 i 4 p 884-885 McAtee R. E 1993 Facilitated Stretching Human KineticsRosenbaun D, Hennig E 1995'The influence of stretching and warm up exercises on achilles tendon activity' Journal of Sports Science vs. 13 p 481-490.