Have you ever wondered why your muscles always seem to feel tight despite spending a lot of time and effort stretching them? Or is there an exercise/ movement that you are unable to perform properly as you are limited by your range? In this case, stretching might not help as it can be due to the lack of mobility instead of flexibility. Many people unknowingly use the terms ‘flexibility’ and ‘mobility’ interchangeably. However, a person with good flexibility does not necessarily mean he or she has mobility (2).
So what is the difference between flexibility and mobility?
Flexibility refers to the ability to lengthen the muscles passively through a range of motion (ROM) where mobility is the ability to actively move a joint through a ROM with control (1, 3). Stretching can help to improve flexibility and there different types of stretching that you can do. Some of the more common stretches are ballistic stretching, active stretching, PNF stretching, and static stretching (3). However, stretching by itself is not enough to improve your mobility.
When it comes to movement, the limbs are often dictated by the mobility of the joint. Unlike flexibility which involves muscles only, mobility involves everything around the joint which includes the connective tissue, synovial membrane, and fluid, cartilage, ligaments, tendons as well as the central nervous system that controls the muscular strength, coordination, and stability (basically it's everything in the system that allow movement) (3). Therefore, if there is a joint mobility issue, stretching alone might not be enough as it can be affected by other factors (s) mentioned.
Then, why is mobility important?
Researches have shown that there is a strong correlation between restricted mobility and various joint pathologies. Patients with hip impingement and labral tear often exhibit a limited ROM in hip flexion, internal rotation, and/or adduction. Likewise, athletes with groin pain were also found to have limited hip ROM (4). Athletes involved in a lot of overhead movements with shoulder impingement tend to have posterior shoulder tightness and poor internal shoulder rotation ROM/ stability (5, 6).
Imagine doing a deep squat for example. Lacking adequate hip mobility can limit our ability to go lower and a couple of things can happen. First, the knees will lose stability and start to cave inward. Second, the lower back will collapse into a rounded position as it is unable to maintain its stability. These can reduce the amount of power generated and increases the risk of knee and lower back injuries.
How to improve mobility?
Improving mobility is a process of reducing muscular contraction, increase muscle flexibility/ range of motion, and muscle re-education (or re-training).
Overactive muscles (always “on”) are constantly “locked” within a range and sooner or later they will lose their ability to move through the full range. Muscles often occur in pairs and as one muscle contracts, the other relaxes. One example would be the biceps and triceps. As the biceps contract, the triceps will have to relax to allow movement (elbow flexion) to occur. Thus, not only the muscle that is constantly switched “on” will lose its range over time, the opposing muscle will eventually be weakened as well (since it’s always in a “relaxed” state). A weak muscle is inclined to fatigue which can also induce the sensation of tightness or stiffness. A common mistake that most people make is to stretch out those weak muscles that feel “tight”. This makes it worse because the muscle is lacking in strength, not flexibility. Therefore, it is necessary to know which are the muscles to stretch or strengthen.
There are several methods to reduce or modulate the activity of the muscle, such as foam rolling, massage guns, and manual techniques like massage and soft-tissue manipulation. This also helps to prepare the muscle for stretching to improve its flexibility. Once the flexibility improves, re-train the muscle with exercises that allow controlled movement (coordination, stability, and strength) through the full range of motion and strengthen the weak muscles before integrating them with functional exercises.
Conclusion
While stretching reduces tightness and improves flexibility, it is important to differentiate between “true” tightness and tightness caused by weakness. It is a step-by-step process and overstretching or forcing yourself into a range will not help with the improvement (it is probably going to get you injured at most). If you are unsure, consider seeking a qualified health/ fitness professional to assess you. Mobility exercises can be done any time (during recovery between exercises or as a program by itself); however, it is recommended to do it before your workout as a warm-up. This helps to prepare your body for movement by improving your overall ROM and control. By incorporating joint mobility exercises into our training program, not only would it help to improve our sports performance and functional movements, but we would also have a much stronger and healthier joint.
References
1) Medeiros, H. B., de Araújo, D. S., & de Araújo, C. G. (2013). Age-related mobility loss is joint-specific: an analysis from 6,000 Flexitest results. Age (Dordrecht, Netherlands), 35(6), 2399–2407.
2) Moreside, J. M., & McGill, S. M. (2013). Improvements in hip flexibility do not transfer to mobility in functional movement patterns. Journal of Strength & Conditioning Research, 27(10), 2635-2643.
3) Phil, P. (2012). Current concepts in muscle stretching for exercise and rehabilitation. International Journal of Sports Physical Therapy, 7(1), 109-119.
4) Nevin, F., & Delahunt, E. (2014). Adductor squeeze test values and hip joint range of motion in Gaelic football athletes with longstanding groin pain. Journal of Science and Medicine in Sport, 17(2), 155–159.
5) Myers, J. B., Laudner, K. G., Pasquale, M. R., Bradley, J. P., & Lephart, S. M. (2006). Glenohumeral range of motion deficits and posterior shoulder tightness in throwers with pathologic internal impingement. The American Journal of Sports Medicine, 34(3), 385–391.
6) Jobe, F. W., Kvitne, R. S., & Giangarra, C. E. (1989). Shoulder pain in the overhand or throwing athlete. The relationship of anterior instability and rotator cuff impingement. Orthopaedic Review, 18(9), 963–975.