Chapter 8 Muscular Flexibility

1. Outline: Benefits of Good Flexibility Factors Affecting Flexibility Assessment of Flexibility Evaluating Body Posture Principles of Muscular Flexibility Prescription When to Stretch? Flexibility Exercises Preventing & Rehabilitating Low-Back Pain Chapter 8Muscular Flexibility

2. When joints are not regularly moved through their full range of motion, muscles and ligaments shorten over time, and flexibility decreases Repetitive movement through regular/ structured exercise as in running, cycling, or aerobics without proper stretching causes muscles and ligaments to tighten Muscular Flexibility

3. Muscular Flexibility Flexibility is the achievable range of motion at a joint or group of joints without causing injury Some muscular/skeletal problems and injuries, related to a lack of flexibility, occur when a tight muscle is abruptly forced beyond its achievable range of motion A decline in flexibility can lead to poor posture and aches and pains that lead to limited, painful joint movement

4. Muscular Flexibility 80% of all low-back problems in the U.S. result from improper alignment of the vertebral column and pelvic girdle as a direct result of inflexible and weak muscles This backache syndrome costs U.S. industry billions yearly in lost productivity, health services, and worker compensation

5. Benefits of Good Flexibility Promotes healthy muscles and joints Improves elasticity of muscles and connective tissue around joints, enhancing freedom of movement Makes activities of daily living (turning, lifting, and bending) easier to perform Regular stretching increases circulation to the muscles Helps prevent low-back and other spinal column problems

6. Benefits of Good Flexibility Improves and maintains good postural alignment Promotes proper and graceful body movement Improves personal appearance and self-image Helps develop and maintain motor skills throughout life

7. Flexibility in Older Adults Older adults lose mobility and may be unable to perform simple tasks such as bending forward or turning Individuals who lose range of motion with age are unable to look over their shoulder to switch lanes or parallel park, increasing the risk for automobile accidents Lack of good range of motion can severely hamper physical activity and exercise

8. Flexibility in Older Adults Lack of flexibility may cause falls and other injury A simple stretching program can alleviate or prevent this problem and help people return to an exercise program

9. Factors Affecting Flexibility Genetic factors Physical activity Joint structure (shape of the bones) Joint cartilage Ligaments Tendons Muscles Skin Tissue injury Adipose tissue (fat) All influence range of motion about a joint

10. Factors Affecting Flexibility Body temperature Age Gender All affect flexibility

11. Factors Affecting Flexibility Changes in muscle temperature can increase or decrease flexibility by as much as 20% Warm muscles are more flexible Cool temperatures impede range of motion Flexibility is affected by the amount of adipose tissue (fat) in and around joints and muscle tissue Excess adipose tissue increases resistance to movement, and the added bulk hampers joint mobility because of the contact between body surfaces

12. Factors Affecting Flexibility Women are more flexible than men and retain this advantage throughout life Aging decreases extensibility of soft tissue, resulting in less flexibility in both sexes Sedentary living is the most significant contributor to lower flexibility because muscles lose elasticity and tendons and ligaments tighten and shorten Adipose tissue increases with inactivity, which decreases a joint’s range of motion Injury to muscle tissue and tight skin from excessive scar tissue negatively effect range of motion

13. Evaluating Body Posture Good posture enhances Personal appearance Self-image Confidence Improves balance and endurance Protects against misalignment-related aches and pains Prevents falls Enhances overall sense of well-being

14. Evaluating Body Posture Poor posture is a risk factor for musculoskeletal problems of the neck, shoulders, lower back, and strains the hips and knees Bad posture, weak and inelastic muscles are a leading cause of chronic low-back problems Proper body mechanics means using correct positions in all activities of daily life, including sleeping, sitting, standing, walking, driving, working, exercising

15. Principles of Muscular Flexibility Prescription Although genetics play a crucial role in flexibility, range of joint mobility can be increased and maintained through a regular stretching program Since range of motion is highly specific to each body part, a comprehensive stretching program should include all body parts and follow basic guidelines for flexibility development

16. Principles of Muscular Flexibility Prescription Overload and specificity of training principles apply to the development of flexibility To increase total range of motion of a joint, the specific muscles around the joint must be stretched progressively beyond their normal length Principles of mode, intensity, repetitions, and frequency of exercise apply

17. Modes of Training Three modes of stretching exercises can increase flexibility Ballistic stretching Slow-sustained stretching Proprioceptive neuromuscular facilitation (PNF) stretching Research shows all three types improve flexibility Each technique has certain advantages

18. Ballistic Stretching Ballistic (or dynamic) stretching: Exercises done with jerky, rapid, bouncy movements May cause muscle soreness and injury from small tears to the soft tissue Precautions must be taken not to overstretch ligaments because they undergo plastic or permanent elongation which leads to excessively loose joints, increasing the risk for injuries Slow, gentle, controlled ballistic stretching is effective in developing flexibility Most people can perform it safely

19. Slow-Sustained Stretching Slow-sustained stretching: Exercises in which the muscles are lengthened gradually through a joint’s complete range of motion and the final position is held for a few seconds Relaxes muscles, achieving greater length Low risk for injury Most frequently used and recommended

20. Proprioceptive Neuromuscular Facilitation (PNF) Proprioceptive neuromuscular facilitation (PNF): Stretching technique that uses reflexes and neuromuscular principles to relax the muscles being stretched Based on a “contract-and-relax” method Partner assisted

21. Proprioceptive Neuromuscular Facilitation (PNF) Procedure is as follows: Assistant provides initial force by slowly pushing in the direction of the desired stretch Person being stretched then applies force in the opposite direction of the stretch, against the assistant who tries to hold the initial degree of stretch, resulting in an isometric contraction at the angle of the stretch The contraction is held 4-5 seconds, then the person being stretched relaxes the muscles and the assistant slowly increases the stretch The procedure is repeated Steps 1-4 are repeated 2-5 times with the final stretch position held for 15-30 seconds

22. Proprioceptive neuromuscular facilitation (PNF) stretching technique: (a) isometric phase (b) stretching phase

23. Proprioceptive Neuromuscular Facilitation (PNF) Theoretically, the isometric contraction helps relax the muscle being stretched, which results in lengthening the muscle Increases strength of the muscle being stretched from the isometric contraction Data shows about 17% and 35% increase in absolute strength and muscular endurance in the hamstring group after 12 weeks of PNF Results were consistent in men and women Disadvantages of PNF are more pain, the need for a partner, time consuming

24. Intensity Degree of stretch to the point of mild discomfort or tightness at the end of the range of motion All stretching should be done slightly below the pain threshold Participants should try to relax the muscle being stretched If you feel pain, the load is too high and may cause injury

25. Repetitions Time required for a flexibility session is based on the number of repetitions and the length of time each repetition is held in the final stretched position General recommendation Each exercise should be done 2-4 times Each time hold the final position 15-30 seconds Gradually increase the time each repetition is held to a maximum of 1 minute Individuals susceptible to flexibility injuries should limit each stretch to 20 seconds Pilates exercises are recommended for these individuals to increase joint stability

26. Frequency of Exercise Flexibility exercises should be performed a minimum of 2-3 days per week, ideally 5-7 days per week After 6-8 weeks, flexibility can be maintained with only 2-3 sessions per week of 3 repetitions of 15-30 seconds each

27. When to Stretch Warming up means starting a workout slowly followed by gentle stretching (not through entire range of motion) A warm-up that progressively increases muscle temperature and mimics movement that will occur during training enhances performance

28. When to Stretch Gentle stretching with warm-up recommended for some activities 3- to 5-minute warm-up for steady activities Up to 10 minutes for stop-and-go activities and athletic participation in general Extensive stretching prior to performing events that rely on strength and power for peak performance is not recommended

29. When to Stretch Evidence is unclear regarding whether stretching before or after exercise is best for injury prevention Good time to stretch is after aerobic exercise due to higher body temperature Stretching helps fatigued muscles reestablish their normal resting length and prevent unnecessary pain

30. Preventing & Rehabilitating Low-Back Pain Over 95% of all back pain is related to muscle/tendon injury 1%-5% is related to intervertebral disc damage Most common cause of low-back pain is physical inactivity, particularly sitting, which causes back muscles to shorten, stiffen, and weaken

31. Incorrect & correct pelvic alignment Weakening of the abdominal and gluteal muscles, along with tightening of the lower back muscles, causes an unnatural forward tile of the pelvis resulting in lower back pain Pelvis tilt is aggravated by fat around the midsection

32. Effects of Stress Excessive stress causes muscles to contract Frequent tightening of the muscles can throw the back out of alignment and constrict blood vessels that supply oxygen and nutrients to the back Chronic stress releases hormones linked to muscle and tendon injuries People under stress forget about proper body mechanics, increasing risk for injury Proper stress management should be in your back care program

33. Personal Flexibility & Low-Back Conditioning Program Recommendations call for isometric contractions of 2-20 seconds during each repetition for some exercises for back health Length of the hold will depend on your current fitness level and difficulty of each exercise Most exercises begin with a 2-10 second hold After several weeks increase the hold to 30 seconds