This is an excerpt fromGuide to Sports Injuries-2. editiondoor Robert Gotlin.
Door Jeff Young, kinesioloog, CSCS, ACSM-EIM
Training flexibility
Flexibility, the available range of motion (ROM) around each joint and mobility, the amount of usable ROM under dynamic, loaded conditions, are important components of both movement and injury prevention (Page 2012, Witvrouw, Mahieu and Danneels 2004). When there are limitations due to lack of flexibility or mobility, movement is less efficient and the risk of injuries increases. Many soft tissue injuries occur during the eccentric (down) phase of a movement, while muscles and tendons are under tension and stretched (lengthening) (Verall and Dolman 2016). If a joint lacks flexibility, maximum or near maximum extension of the muscles around the joint will occur earlier in a movement. If this happens under load, damage can occur. To reduce this risk, flexibility must at least be distributed around each key link (see Figure 2.1).
To objectively know whether a joint has limited range of motion, is within normal limits, or is hypermobile, an assessment must be performed at each major joint. It is the athlete's responsibility to have a joint ROM assessment performed by a qualified professional. Once this is achieved, the athlete can follow an appropriate flexibility training program to balance flexibility around each major joint.
Designing a flexibility program follows a principle known as FITT. The letters stand for Frequency, Intensity, Time (duration) and Type.
Frequency
A stretching program should be initiated even if the athlete has normal joint ROM in each joint. In that case, the minimum recommendation of twice a week would be sufficient to maintain joint ROM. Increased tightness or restriction of movement requires an increase in volume. This can be achieved by increasing frequency or sets, or both: the tighter an athlete is, the more stretches are required. Therefore, joints that do not conform to normal range of motion (i.e., restricted or "tight" areas) should be stretched three to seven days per week (Garber et al. 2011). Stretching must be done correctly and safely. Improper stretching has been shown to increase injury.
Intensity
Intensity lies on a subjective continuum of discomfort or pain, ranging from a 'gentle' stretch to 'mild discomfort', 'moderate discomfort', 'very uncomfortable' or 'painful'. Interestingly, all levels of discomfort, including stretching to a point of pain (Muanjai, Jones, and Mickevicius 2017), have been shown to increase flexibility. Logically, stretching to the point of pain is not recommended, and current evidence recommends stretching to the point of mild to moderate discomfort (Garber et al. 2011).
Time
The duration of the stretches covers a continuum ranging from 10 to 15 seconds to several minutes. If the goal is to increase joint range of motion, total stretch time over multiple sets is most important. Athletes therefore have the option of holding a stretch for longer (e.g. 90 seconds) or dividing the total time into multiple sets (e.g. three sets of 30 seconds) (Frietas et al. 2014).
Type
The different types of stretching include active, passive, dynamic, static, isometric and proprioceptive neuromuscular facilitation (PNF). Dynamic stretching is the preferred form of stretching as part of a warm-up before a workout or event. The other forms of stretching have been shown to be superior in the short term, but all forms of stretching can improve joint mobility when performed correctly (Garber et al. 2011, Guissard and Duchateau 2006, page 2012).
It is important to note that muscles are viscoelastic (Ryan et al. 2009, 2012). The viscoelastic property of muscles allows them to be deformed (stretched); and although elasticity also allows it to return to its original shape, joint ROM can increase above baseline values through flexibility training. If the goal is to maintain joint range of motion, athletes should stretch until they reach an "end-range feeling" for the given stretch (i.e., the feeling that it would be painful to continue further into the stretch), hold, and release. However, if the goal is to increase joint range of motion, they should stretch until they reach their end range, hold, mentally relax into the stretch, and then increase the stretch to a new end range. This is known as muscle creep, or 'crawling further into the stretch', and the viscoelastic properties of the muscles, together with the relaxation of the nervous system during the stretch, make this possible. The bottom line: When athletes want to increase joint range of motion, but only stretch to their first end range (without using muscle creep and neural relaxation that allow for increases in range of motion), the body is not getting a signal to continue to go and the stretching exercise will take place. be fruitless. It is imperative to remember to find a second and, if possible, a third end zone within each sequence of a play if the goal is to improve flexibility.
Self-myofascial release (SMR) is another method of increasing joint mobility, and while SMR will not directly reduce the risk of injury as it helps improve ROM and can also increase performance, it should be included as part of a flexibility training program. and warm-up (Beardsley and Skarabot 2015, Schroeder and Best 2015). Although it is beyond the scope of this chapter to provide significant details, SMR follows the FITT protocol and should be used concurrently with stretching, usually just before performing various stretches. See Cheatham and colleagues (2015) for more information.
More excerpts from the Sports Injuries Guidebook 2nd Edition