Two interconnected concepts
Flexibility refers to the passive range of motion available at a joint. In simple terms, it describes how far muscles, tendons and other soft tissues can be lengthened. For example, if a physiotherapist gently lifts your leg towards your chest, the movement is being created by an external force rather than by your own muscles.
Mobility is the active counterpart to flexibility. It describes your ability to move a joint through a range of motion using your own strength, balance and coordination. The question is not simply whether your leg can reach a certain height, but whether you can lift it there and lower it again with control.
Although flexibility contributes to mobility, it is not enough on its own. A joint may have an excellent range of motion, but if the surrounding muscles are weak or the nervous system cannot coordinate the movement efficiently, that range cannot be used effectively. True mobility depends on three elements working together: sufficient flexibility, adequate strength, and good muscular and neurological control.
A useful comparison is learning to play the piano. Flexible fingers alone do not produce music. You also need the strength to press the keys and the coordination to strike them accurately. In the same way, mobility is an active skill rather than simply a passive physical attribute.
Why both decline with age
The changes associated with ageing are driven by measurable physiological processes rather than simply the passage of time.
As we grow older, collagen fibres form additional cross-links, making tendons and joint capsules stiffer and less elastic. Cartilage gradually loses water content, and joints may produce less synovial fluid, which can make movement feel less smooth and comfortable.
At the same time, age-related muscle loss, known as sarcopenia, causes declines in both muscle mass and strength. Muscle strength typically decreases by around 10 to 15 per cent per decade after midlife, and the rate of decline often accelerates in later years. In addition, changes within the nervous system can slow reaction times and reduce coordination.
These changes affect flexibility and mobility differently. Ankle mobility, for example, declines noticeably with age, reducing the ability to walk efficiently, maintain balance and recover from a stumble. Many older adults also experience substantial losses in muscle strength compared with their younger years. Because mobility relies on flexibility, strength and motor control working together, it often deteriorates more quickly than flexibility alone.
Why this matters for independence
The consequences of reduced flexibility and mobility extend far beyond athletic performance. They influence how safely and confidently we move through everyday life.
Poor mobility is a major predictor of falls in older adults because it affects balance, stability and the ability to react to unexpected challenges. A joint with moderate flexibility but good muscular control is generally more stable than a highly flexible joint that lacks strength and coordination.
Many of the tasks we perform every day are fundamentally mobility tasks. Rising from a chair, climbing stairs, reaching into a cupboard, stepping into a bath, or turning to check a blind spot while driving all require a combination of range of motion, strength and control.
When movement becomes difficult, people often begin to avoid it. Reduced activity then leads to further losses in strength and mobility, creating a self-perpetuating cycle of decline. Over time, this can result in reduced confidence, reduced physical function and an increased reliance on others for assistance.
Ultimately, flexibility helps keep movement comfortable, while mobility helps keep people independent.
The practical guide to training both
The encouraging news is that flexibility and mobility can both be improved at almost any age.
To maintain or improve flexibility, aim for at least two to three stretching sessions each week. Focus on major muscle groups such as the calves, hamstrings, hips, chest and shoulders. Hold each stretch for between 10 and 30 seconds and repeat it two to four times. A simple seated hamstring stretch, performed gently and without bouncing, is an effective example.
To improve mobility, include controlled movement exercises and strength training in your routine. Dynamic exercises such as leg swings, hip circles and controlled lunges encourage joints to move through their available range. Resistance training is particularly effective because it develops strength throughout a movement while simultaneously improving control.
Exercises do not need to be complicated. Slow sit-to-stands, step-ups, bodyweight squats and single-leg balance exercises all develop the qualities needed for everyday movement.
A perfect example: The sit-to-stand
If one exercise demonstrates the importance of mobility, it is the sit-to-stand.
Standing up from a chair may appear simple, but it requires several physical systems to work together. The quadriceps and gluteal muscles must generate sufficient force to extend the hips and knees. The ankles need adequate range of motion to maintain a stable foot position. Balance and coordination are required as the body’s weight shifts during the movement.
Just as importantly, lowering yourself back into the chair demands control, not merely strength. This mirrors many of the physical challenges encountered in daily life, from climbing stairs to walking safely and changing direction.
Exercises that closely resemble everyday movement patterns tend to provide the greatest practical benefit because they develop the specific abilities required to remain active and independent.
In summary, stretching plays an important role in maintaining flexibility and comfortable movement, but flexibility alone is not enough to preserve function as we age. Mobility, which combines range of motion, strength and control, is what allows us to move confidently through daily life.
The goal is not to choose between stretching and strength training. The most effective approach is to combine both. Regular stretching helps maintain joint range of motion, while strength-based movement develops the stability and control needed to use that range effectively.
By consistently training both flexibility and mobility, it is possible to maintain confidence, function and independence well into old age.
