Flexibility is a component that is becoming less frequently overlooked when training in gyms and during sporting events. People are becoming more aware of injury susceptibility in muscle groups that are tight and joints that are less flexible. This blog will discuss stretching types and a few ways in which you can increase flexibility depending on what you want to achieve.
What is Muscle Flexibility?
Muscle flexibility is defined as ‘the ability of a muscle to lengthen allowing one joint (or more than one joint in series) to move through range’ (Zachezweski et al, 1989). Reduced flexibility is therefore a reduced range of movement available in said joints due to the reduced ability for the muscles to lengthen fully. There is considerable evidence, which demonstrates that stretching prevents injury, improves recovery from injury and can affect physical performance prior to sport.
Stretching and flexibility are seen as components of a warm-down for many amateur sporting groups, but research has highlighted how important it is introduce stretching into the warm-up routine also. Dynamic stretching has been implemented as one of the new ‘buzzwords’ within a gym. This is due to the apparent negative effect which static stretching has on immediate physical performance after a warm-up, although dynamic stretching does appear to have pitfalls in injury management and recovery.
Types of Stretching
There are considered to be three main types of stretching methods for muscle flexibility. These are static stretching, dynamic stretching and proprioceptive neuromuscular facilitation (PNF). There has been lots of research to evaluate the effectiveness of each stretching type, and it shows that although each method has the ability to greatly improve flexibility, there are differences between the three.
To illustrate the ways in which static stretching, dynamic stretching and proprioceptive neuromuscular facilitation (PNF) differs, let’s look at the way a hamstring stretch is executed using each method.
Static stretching is what people usually associate with ‘stretching’. This usually consists of holding the muscles in their maximal lengthened position (at the point of discomfort) for around 30 seconds. This is then repeated a number of times with short rest between each stretch. Hamstrings are stretched in this way by the knee being held straight, and the individual bending down towards their toes by bending at the hip.
Dynamic stretching is the method of stretching the muscle in question while a gross movement of the limb/joint is being made. A commonly seen dynamic stretch of the hamstring is where the individual stands and with the knee being kept straight, the leg is swung back and forth with the movement coming from the hip. This aims at further stretching the muscle group using the velocity of the limb ‘swing’.
Proprioceptive Neuromuscular Facilitation (PNF)
Proprioceptive Neuromuscular Facilitation (PNF) is when the muscle is contracted in an already fully lengthened position. This is used commonly by physiotherapists in both the sporting realm and at outpatient clinics. Continuing with the example of hamstring stretching, the physiotherapist will place these muscles in a stretch by flexing the hip and extending the knee until the client feels discomfort in the knee. The client will then maximally contract hamstrings as much as possible while the therapist resists the movement. This is held for around 10 seconds, before the client maximally relaxes, and the therapist stretches the muscle further into range.
Use of Each Stretching Method
There has been lots of research identifying the benefits of each stretching method in different scenarios. Notably most of these researches are using active outcome measures (i.e. jump height, weighted strength exercises or sprint speed) when comparing the effectiveness of each stretching method (Yamaguchi, 2005; Little et al, 2006; Herda et al, 2008; Hough et al, 2009).
Each of these research articles identified that dynamic stretching and PNF had a better outcome on this active performance than static stretching held for an average of 30 seconds. This may be due to the stretching method requiring repeated contraction of the muscle during the limb swing or therapist resistance. The analysis of these papers identify that this improvement in the outcomes could possibly be due to the repeated contractions of the muscle which could have a similar effect to a warm-up in increasing blood flow to the area and stimulating the nerve supply to improve contractibility.
Static stretching however, has been shown to improve passive range more effectively and quickly than dynamic stretching and PNF when tested on previously injured individuals (O’Sullivan et al, 2009). In this study, static stretching was shown to increase flexibility significantly more than dynamic stretching, and that this flexibility was more easily maintained with static stretching alone.
These findings agree with current research that static stretching should be used if the aim of the stretching program is to increase flexibility and range of movement over a joint. If the aim of the stretch is for preparation prior to sporting intervention and muscle strength, then PNF and dynamic stretching would be more appropriate.
Flexibility Training and You
If you are seeing a therapist for flexibility training, they should be tailoring your exercises and stretching type depending on the treatment goals you want to achieve. Flexibility training can help you with your performance in the gym and prior to sporting events, so it should be established into a warm-up regime.
If you have any questions regarding flexibility and what stretches you should include in your routine, please contact Physiocomestoyou to arrange a treatment session.
Herda et al (2008) – Acute effects of static vs dynamic stretching on isometric peak torque, electromyography and mechanomyography of the biceps femoris muscle: Journal of Strength and Conditioning Research 22(3) (p809-17)
Hough et al (2009) – Effects of Dynamic and Static Stretching on Vertical Jump Performance and Electromyographic Activity: Journal of Strength and Conditioning Research 23(2) (p507-12)
Little et al (2006) – Effects of differential stretching protocols during warm-ups on high-speed motor capacities in professional soccer players: Journal of Strength and Conditioning Research 20(1) (p203-7)
O’Sullivan et al (2009) – The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects: BMC Musculoskeletal Disorders 10(37)
Yamaguchi and Ishii (2005) – Effects of static stretching for 30 seconds and dynamic stretching on leg extension power: Journal of Strength and Conditioning Research 19(3) (p677-83)
Zachezweski et al (1989) – Improving Flexibility: Physical Therapy (p698-99)