Stretching for increased flexibility.
As a qualified sports therapist for the best part of 14 years the subject I probably get asked about the most is stretching.
How long should I hold a stretch?
How often do I do it?
What type of stretch is best?
These questions are regularly asked but unfortunately there is not a straightforward reply to any of them. A lack of definitive research makes it difficult to give accurate and consistent answers.
Generally stretching exercises are used to increase flexibility which can be defined as the range of movement available at a joint(s). Whether it is to carry out our normal daily activities or to participate in the majority of sporting activities, it is necessary to have normal range of movement at any given joint(s). It has been suggested that a lack of flexibility can increase the risk of musculoskeletal injuries1 as reduced muscle flexibility may restrict joint range of movement creating abnormal movement patterns. For example shortened calf muscles may restrict ankle dorsiflexion, causing an altered gait pattern while running or walking. This may produce a compensatory pattern of walking, with a laterally turned out foot, eventually leading to pain in the hip or knee.
Some of the more common methods of stretching for increasing flexibility are proprioceptive neuromuscular facilitation (PNF), ballistic, dynamic range of motion2 and static stretches.
Proprioceptive neuromuscular facilitation
The PNF technique involves a voluntary muscular contraction, usually of the muscle to be stretched, to promote relaxation and subsequently increase flexibility3. This technique usually requires the assistance of a trained therapist and is therefore limited in its use. As a guide, a six second contraction followed by a 10 to 30 second assisted stretch is suggested by the American College of Sports Medicine (ACSM)4.
Ballistic
Ballistic stretching involves repetitive bouncing movements using the momentum of a swinging body part to lengthen a muscle. Although ballistic stretching can produce an increase in flexibility this form of stretching has fallen out of favour with therapists in recent years, as it is feared the rapid increase in tension could cause a strain or rupture of the muscle2.
Dynamic range of motion
Dynamic range of motion stretching, a method gaining in popularity, is where the opposite muscle to the one being stretched is contracted in order to lengthen the muscle being stretched in a slow controlled manner2. For example, contraction of the quadriceps muscles to extend the knee will lengthen the hamstrings.
Static
Probably the most common stretch to be used is the static stretch5. This involves taking a muscle, or group of muscles, to their end of range of movement, until the point of mild discomfort, and holding that position for a period of time. According to the ACSM guidelines4 static stretches should be held for 15 to 60 seconds repeated up to four times at least two to three days per week.
Bandy and Irion concluded6 a single stretch of 30 or 60 seconds five days per week for six weeks was more effective than a 15 second stretch in increasing muscle flexibility. However, there was no significant difference found between the 30 second and 60 second stretch suggesting the longer duration stretch is unnecessary. The participants of this study were relatively young with an average age of 26 years therefore these conclusions should only be applied to this age group.
A further study7 looking at the effects of stretch duration in the elderly, average age 85 years, demonstrated that a 60 second stretch repeated four times, five days per week produced greater improvement in flexibility than similar regimens of 15 and 30 seconds duration.
The findings of these two studies may explain why the ACSM give wide guidelines of 15 to 60 seconds duration, it is possible that the ideal time a static stretch should be held is dependant on age.
It should also be noted both these studies only examined the effects on hamstring flexibility. It is clear further research examining the effects on other muscles and covering a wider population is required.
Conclusion
Generally all the stretches discussed will increase flexibility, but the static stretch is probably the safest and simplest to carry out alone. The advice of a qualified therapist should be sought before undertaking a flexibility programme in order to learn correct stretching technique for the muscle requiring lengthening. It should also be pointed out that stretching alone may not always the answer and could even be the wrong thing to do.
About the author
As a sports therapist Russell Milton has been involved in both private practice and professional sport. He regularly attends courses to keep up to date and further his knowledge, demonstrating his commitment to continual professional development.
Also having suffered two major injuries himself, ACL rupture and AC joint dislocation, Russell is able to empathise with his patients.
Russell runs 'The Milton Clinic', sports injury treatment and rehabilitation centre, in Crawley and can be contacted on 01293 427492.
Website: www.themiltonclinic.co.uk
References
1 Worrell TW, Perrin DH, Gansneder BM and Gieck JH (1991) ‘Comparison of isokinetic strength and flexibility measures between hamstring injured and non-injured athletes’, The Journal of Orthopaedic and Sports Physical Therapy; 13 (3): 118-125
2 Bandy WD, Irion JM and Briggler M (1998) ‘The effect of static stretch and dynamic range of motion training on the flexibility of the hamstring muscles’, Journal of Orthopaedic & Sports Physical Therapy; 27 (4) 295-300
3 Knott m and Voss D (1968) Proprioceptive Neuromuscular Facilitation: Patterns and Techniques, Harper and Row, New York
4 ACSM (2010) Guidelines for Exercise Testing and Prescription 8th edition. Lippincott, Williams & Wilkins, Baltimore MD
5 Roberts JM and Wilson K (1999) ‘Effect of stretch duration on active and passive range of motion in the lower extremity’, British Journal of Sports Medicine; 33 (4): 259-263
6 Bandy WD and Irion JM (1994) ‘The effect of time on static stretch on the flexibility of the hamstring muscles’, Physical Therapy; 74 (9): 845-850
7 Feland JB, Myrer JW, Schulties SS, Fellingham GW and Measom GW (2001) ‘The effect of duration of stretching of the hamstring muscle group for increasing range of motion in people aged 65 years or older’, Physical Therapy; 81 (5): 1110-1117
