Stretching is a well-researched topic within the fitness industry. Do we need to do it? What are the effects of doing it? What are the different ways of stretching? Such questions are often asked by clients of their trainers.
At VFA Learning students are educated on the theory of stretching and then transfer this knowledge into the gym setting practically throughout their time completing the Certificate III and IV in Fitness and then furthermore in the Diploma of Sport Development course.
To stretch can be defined as; to be made or be capable of being made longer or wider without tearing or breaking (according to a simple Google search). We aim to do this with our soft tissues (muscles and tendons) in order to;
- Improve ranges of motion about the joints and increase flexibility of the muscle tissue
- Improve feelings of relaxation and ‘looseness’ post stretching
- Reduce the likelihood of injury (the cause of much discussion and research)
This is achieved by reducing the ‘stiffness’ of the muscle and tendon structures. Several hypotheses have been proposed to explain the stretch-induced decreases in musculotendinous stiffness including;
- Increases in tendon compliance (Kubo, Kanehisa, Kawakami, & Fukunaga, 2001)
- Increases in fascicle length (Fowles, Sale, & Mac-Dougall, 2000)
- Non-contractile protein elongation (i.e. titin and desmin) (Gajdosik et al., 2005)
However, recent evidence suggests that the deformation of intramusuclar connective tissue, rather than tendon compliance or muscle fascicle length changes, may be primarily responsible for the decreases in musculotendinous stiffness and improved ROM (Morse, Degens, Seynnes, Maganaris, & Jones, 2008).
While all sounding quite technical, we need to remember that the musculotendinous soft tissue structures have two capabilities, these being elasticity and plasticity.
Elasticity means that the structure will return to its original shape or length following deformation or elongation. Plasticity however represents the tissues ability to change shape or length permanently. It is this feature that is the reason stretching can improve our range of motion and posture. Unfortunately it takes weeks to months of consistent stretching to elicit such improvements. Fortunately, the elastic properties of the muscle means clients can experience rapid improvements in ranges of motion and flexibility.
The breakdown of Stretching:
So how long should we stretch for and how often? Well, EVERY DAY! And 1-3 times per day if practically possible. But consistency is the key to improvement. To improve passive ROM and reduce musculotendinous stiffness it has been suggested;
- 15 seconds to an hour! (Boyce & Brosky 2008)
- 5x15sec passive static with no significant improvements thereafter (10x15sec), with 1st stretch providing greatest improvements (Boyce & Brosky 2008)
- 2x30sec passive (Ryan et al 2009)
- 30sec accumulative irrespective of frequency and duration (Australian Strength and Conditioning Association level 3 lecture notes)
- 1 min accumulative (Australian Strength and Conditioning Association level 3 lecture notes)
To summarise the research, at least 30 seconds is the minimum with 60 seconds being a somewhat optimal duration to hold a stretch. Just make sure you focus on breathing throughout to help relax your muscles.
And how should we stretch?
Proprioceptive Neuromuscular Facilitation (PNF) is one of the best forms for stretching to see an immediate impact in improvements of flexibility and range of motion. How is this performed? Well a stretch is applied for a duration of 10-30 seconds for a given muscle group, followed by an isometric contraction (tension created within the muscles with no movement) performed for at least 3-10 seconds. The intensity of the contraction should be between 20-50% of maximum effort according to the scientific literature. A subsequent stretch will see (hopefully) an improvement in the range of which the muscle can move. This process can be repeated several times to gain better results (Sharman et al, 2006).
Stretching how does it work?
While the true physiological mechanism may be unknown, the proposed mechanisms for the improvements are autogenic inhibition. This sees a sensory organ within the tendon, known as a Golgi Tendon Organ (GTO) create a response that sees the muscle that has just contracted and created tension, relax and allow the muscle to be moved through a greater range. The initial stretch needs to held for a period greater than 10 seconds, reportedly affecting another sensory organ, the muscle spindle, which responds to stretch causing a contraction followed by a relaxation phase after the extended stretch desensitises the spindles causing relaxation within the muscle (stress relaxation), again allowing it to be moved through a greater range.
Does stretching help to prevent injury?
Well literature review articles state no significant injury prevention/protection effect from stretching (Shrier, 1999). It has been stated that “There is not sufficient evidence to endorse or discontinue routine stretching before or after exercise to prevent injury among competitive or recreational athletes” (Thacker et al 2004, p.371). However continual avoidance of stretching as a part of the weekly training regime will lead to shortened muscles, resisted joints and postural issues that can lead to injuries through repetitive movements under loading. So a stretch before your session may not necessarily results in a reduced likelihood of injury for that session, but over time the effects of poor flexibility and limited range of motion about a joint may in fact result in injury.
So get stretching!
By David Kinsella, 2015.
Safram, Garrett, Seaber, Glisson & Ribbeck 1988, The role of warm up in muscular injury prevention, 16(2), The American Journal of Sports Medicine.
Young, Clothier, Otago, Bruce, Liddell, 2004, Acute effects of static stretching on hip flexor and quadriceps flexibility, range of motion and foot speed in kicking a football, 7(1), Journal of Science and Medicine in Sport.
Ryan, Herda, Costa, Defreitas, Beck, Stout & Craemer, 2009, Determining the minimum number of passive stretches necessary to alter musculotendinous stiffness, 27(9), Journal of Sports Sciences.
Hadala & Barrios, 2009, Different strategies for sports injury prevention in an america’s cup yachting crew, 41(1), Medicine and Science in Sports and Exercise.
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