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Objectives
Identify factors contributing to joint stability and flexibility.
Discuss role of proprioceptors in musculotendinous stretching exercises
Discuss characteristics of effective flexibility exercises, including PNF
Review common joint injuries
Joint flexibility – Range of Motion (ROM) Static vs dynamic Active vs passive Measuring joint range of motion
- Direct measurement – • Goniometer (Fig 5.9, p 127)• Leighton flexometer (Fig 5.10, p 127)
- Indirect & composite – e.g., sit and reach Factors influencing joint flexibility
- Shape of articulating bone surfaces (ex.: forearm extension)- Intervening muscle and fat (ex. : forearm flexion)- Length of ligaments and musculotendinous units crossing joint
Flexibility and injury – - Increased potential for injury when ROM is high, low, or imbalanced
Techniques for increasing joint flexibility Focus is on increasing length of musculotendinous units crossing
the joint Neuromuscular response to stretch
- The sensory unit• Consists of receptors, sensory neuron• Role is to provide feedback to provide body position and muscle-tendon condition
sense & to enable motor control
- Proprioceptors • Tendon receptors (stretch-sensitive golgi tendon organ, or GTO)
– Stimulation inhibits contraction of host muscle and tendon
• Muscle receptors (stretch-sensitive muscle spindle)– Excitation facilitates contraction of host muscle
- Role of proprioception in skilled movement & flexibility Goal of proprioceptive neuromuscular facilitation (PNF) stretching technique is to
minimize spindle effect and maximize GTO effect.
Increasing flexibility Active and passive stretching Ballistic and static stretching Proprioceptive Neuromuscular Facilitation:
Proprioceptive Neuromuscular Facilitation (PNF)
A group of stretching procedures involving alternating contraction and relaxation of the muscles being stretched.
Done to take advantage of GTO and muscle spindle response.
Many of the techniques require partner or clinician- Contract-relax-antagonist-contract technique- Contract-relax and hold-relax methods
Can significantly increase joint ROM over single stretching session.
Example of PNF Stretching using hamstrings
Passive stretch of hams by partner Contract hams against partner resistance (inhibits
hams via GTO excitation)- Isometricly or concentricly
Relax hams, contract quads (inhibits hams further through reciprocal inhibition via spindle excitation)- Isometricly or concentricly
Passively stretch hams Both methods involve 4-8 reps of 10-15 seconds
duratin or longer
Common jt injuries and pathologies Sprains- stretching or tearing of ligaments, tendons, and
connective tissues crossing a joint Dislocations – displacement of the articulating bones at a joint Bursitis – inflammation of bursae Arthritis – inflammation with pain and swelling
- Rheumatoid arthritis• autoimmune system disorder
- Osteoarthritis• Joint-specific, due to wear and tear
Website on bone and joint injuries: - http://www.arthroscopy.com/
Self-study problems: Introductory problems, p 136: 3,,5,7,10;- Additional problems, p 137: 7- Also, take quiz for Chapter 5 on text website