Flexibility: Definition, Training and Health

What is Flexibility?

Flexibility describes the ability of the human body to move joints and surrounding structures such as muscles, tendons, and ligaments through their full range of motion (ROM). It is considered one of the fundamental components of physical fitness and is closely linked to health, performance, and quality of life.

A distinction is made between active flexibility, in which movement is produced by the individual's own muscular effort, and passive flexibility, in which an external force such as a therapist or device supports the movement. Passive flexibility is generally greater than active flexibility.

Factors Influencing Flexibility

A person's flexibility is influenced by numerous factors:

• Joint anatomy: The shape and structure of a joint determine its maximum range of motion.
• Muscle and connective tissue properties: Tight or shortened muscles and less elastic connective tissue reduce flexibility.
• Age: The elasticity of muscles and connective tissue naturally decreases with age.
• Sex: Women tend to have greater innate flexibility than men.
• Body temperature: Warmed tissue stretches more easily, which is why warming up before stretching is recommended.
• Physical inactivity: Prolonged limited movement leads to muscle shortening and stiffness.
• Diseases and injuries: Conditions such as osteoarthritis, inflammation, or scar tissue can significantly reduce flexibility.

Importance for Health

Good flexibility contributes substantially to health and well-being. It helps to:

• Prevent injuries by making joints and muscles more resilient,
• Reduce postural problems and chronic back pain,
• Promote blood circulation and relieve muscle tension,
• Improve everyday movement patterns and athletic performance,
• Support independence and fall prevention in older adults.

Reduced Flexibility

Restricted flexibility can have various causes and affect different areas of the body. Common causes include:

• Muscle tension due to stress, poor posture, or overuse,
• Osteoarthritis or other degenerative joint diseases,
• Inflammatory conditions such as rheumatoid arthritis,
• Injuries such as muscle strains, ligament tears, or bone fractures,
• Scar tissue following surgery or injury,
• Neurological conditions affecting muscle control.

Diagnosis and Measurement

Flexibility is assessed using several methods in medical and therapeutic practice:

• Goniometry: Measurement of joint angles using a goniometer (angle-measuring device), the standard method in physiotherapy,
• Functional tests: such as the finger-to-floor distance test for assessing back and hamstring flexibility,
• Imaging methods: X-ray or MRI to evaluate structural causes of restricted movement.

Treatment and Improvement of Flexibility

Flexibility can be improved through targeted training and therapeutic interventions:

Stretching Techniques

• Static stretching: A stretch position is held for 20–60 seconds. Suitable for recovery and general flexibility improvement.
• Dynamic stretching: Controlled, bouncing movements within the range of motion. Especially useful as a warm-up before physical activity.
• PNF stretching (Proprioceptive Neuromuscular Facilitation): An advanced technique involving alternating contraction and relaxation of the muscle to achieve a deeper stretch.

Physiotherapy

When flexibility is pathologically restricted, for example after injuries or in the presence of joint disease, targeted physiotherapeutic treatment is recommended. This includes manual therapy, mobilization techniques, and individually tailored exercise programs.

Yoga and Pilates

Both movement forms combine stretching, strengthening, and coordination, and are scientifically supported as effective methods for improving flexibility and posture.

Heat and Cold Therapy

Heat applications (e.g., a heat pad, infrared light, sauna) increase tissue elasticity before stretching. Cold therapy can be used to manage inflammation and swelling, helping to maintain flexibility over time.

Recommendations for Flexibility Training

The World Health Organization (WHO) recommends that adults incorporate regular flexibility exercises into their routine alongside endurance and strength training. The following principles are scientifically supported:

• At least 2–3 training sessions per week,
• Hold each stretch position for at least 20–30 seconds,
• Stretch when the body is warmed up (after light activity),
• Never stretch to the point of pain, only to the point of mild tension.

References

1. World Health Organization (WHO): Global recommendations on physical activity for health. Geneva, 2010. Available at: https://www.who.int/publications/i/item/9789241599979
2. Behm, D.G. et al. (2016): Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals. Applied Physiology, Nutrition, and Metabolism, 41(1), 1–11. PubMed: PMID 26642915.
3. Kisner, C. & Colby, L.A. (2018): Therapeutic Exercise: Foundations and Techniques. 7th Edition. F.A. Davis Company, Philadelphia.