FEXIBILITY AND LOW-BACK HEALTHChapter 9

Test your knowledge•Stretching exercises should be performed

▫At the start of a warm-up▫First thing in the morning▫After endurance exercise or strength

training

C. it’s best to do stretching exercises when your muscles are warm. Stretching muscles before exercise may temporarily reduce their explosive strength and interfere with neuromuscular control.

Test your knowledge•If you injure your back, it’s usually best to

rest in bed until the pain is completely gone. True or False?

FALSE. Prolonged bed rest may actually worsen back pain. Limit bed rest to a day or less, treat pain and inflammation with cold and then heat, and begin moderate physical activity as soon as possible.

Test your knowledge•It is better to hold a stretch for a short

time than to “bounce” while stretching. True or false?

TRUE. “Bouncing” during stretching can damage your muscles. This type of stretching, called ballistic stretching, should be used only by well-conditioned athletes for specific purposes. A person of average fitness should stretch slowly, holding each stretch for 15 – 30 seconds.

Flexibility•Ability of a joint to move through its

normal, full rage of motion.

2 types: Static flexibility ability to hold an

extended position at one end or point in a joint’s range of motion

Dynamic flexibility ability to move a joint through its range of motion with little resistance. Involves strength, coordination and resistance to movement.

What determines flexibility?•The flexibility of a joint is affected by

▫Structure▫Muscle elasticity▫Length▫Nervous system regulation

Joint structure• Joint capsule

▫ Provides support and stability to the joint

• Cartilage

• Synovial fluid▫ Cushions the bones and

reduces friction

• Ligaments▫ Found on both inside and

outside the joint capsule▫ Serve to strengthen and

reinforce the joint.

Joint structure•Hinge joint

•Ball – and – socket joint

Muscle elasticity and length• Soft tissues limit the flexibility of a joint

▫ Skin, muscles, tendons, and ligaments

▫ Muscle tissue is the key to develop flexibility Connective tissue: provides structure, elasticity and bulk

Collagen: white fibers, provide structure and support Elastin: yellow fibers, provide elasticity and flexibility

▫ Regular stretching contributes to flexibility by lengthening muscle fibers through the addition of contractile units called sarcomeres.

Nervous system regulation• Proprioceptors: nerves that send information

about the muscular and skeletal systems to the nervous system.

• Control the speed, strength and coordination of muscle contractions.

• Proprioceptors adapt very quickly to stretching (or lack of stretching). Frequent training is beneficial for developing flexibility

• Stretches than involve rapid, bouncy movements can cause injury.

• Performing a gradual stretch and then holding it allows the proprioceptors to adjust to the new muscle length and to reduce the signals sent to the spine, allowing muscles to lengthen and over time to become more flexible.

Benefits of flexibility and stretching exercises

• Joint health▫Poor joint flexibility can

cause: Abnormalities in joint

lubrication Joint deterioration Expose joint to abnormal

stresses▫Good joint flexibility

Prevents arthritis Lessens pain Increases balance and

stability

Benefits of flexibility and stretching exercises

• Prevention of low-back pain and injuries

▫ Low-back pain is related to poor spinal stability

▫ Strength and flexibility in the back, pelvis and thighs may help prevent this type of pain.

▫ Good hip and knee flexibility protect the spine from excessive motion.

▫ Overstretching may decrease the stability of a joint, increasing the risk of injury

Benefits of flexibility and stretching exercises • Relief of aches and pains

• Relief of muscle cramps▫ Related to increase electrical activity within the

affected muscle

• Improved body position and strength for sports and life. ▫ Lets you assume more efficient body positions

and exert force through a greater range of motion.

• Maintenance of good posture and balance▫ Contributes to body symmetry and good posture

• Relaxation▫ Reduce mental tension, slows breathing rate,

reduces blood pressure.

Lab 9.1

•ASSESSING FLEXIBILITY

Creating a successful program to develop flexibility•Your goal should be to attain normal

flexibility in the major joints.

•Extreme flexibility causes joint instability which can lead to pain in the back, hips, shoulders and knees.

•Balanced flexibility provides joint stability and facilitates smooth movement patterns.

Apply the FITT principle•Frequency

▫2-3 days a week – ideally 5-7 days a week▫Stretch when your muscles are warm▫Pre-exercise stretching decreases muscle

strength and performance and disturbs neuromuscular control.

• Intensity and time▫Slowly stretch your muscles to the

point of slight tension or mild discomfort.

▫Hold the stretch for 15 – 30 seconds

▫Try to stretch a little bit farther▫During the stretch try to relax and

breath easily▫Rest 30 – 60 seconds between

each stretch▫Do 2-3 repetitions of each stretch▫A complete flexibility workout

usually takes about 20- 30 min.

•Types of stretching techniques▫Static stretching

Each muscle is gradually stretched and the stretch is held for 15 – 30 seconds.

▫Ballistic stretching The muscles are stretched suddenly in

a forceful bouncing movement. Recommended only for well trained

athletes

•Types of stretching techniques▫Dynamic (functional) stretching

Involves moving the joints through the range of motion used in a specific exercise or sport in an exaggerated but controlled manner.

• Types of stretching techniques▫Proprioceptive neuromuscular Facilitation –

PNF Uses reflexes initiated by both muscle and joint

nerves to cause greater training effects Contract – relax stretching: the muscle is contracted

before it is stretched. Contract – relax – contract stretching: begins with

the contraction of the muscle to be stretched, then relaxing it and then contracting the opposing muscle (antagonist), finally relaxing the first muscle.

•Types of stretching techniques▫Passive vs. active stretching

Passive stretching An outside force or resistance provided by

yourself, a partner, gravity or a weight helps your joints move through their range of motion.

Active stretching A muscle is stretched by a contraction of the

opposing muscle

Exercises to improve flexibilityWarm up 5-10 minutes or following an endurance or strength training workout

Stretching exercises for major jointsSample program

Exercise Areas stretchedHead turns and tilts Neck

Towel stretch Triceps, shoulders, chest

Frequency: 2-3 days/week; 5-7 days/week idealIntensity: stretch to the point of mild discomfort, not pain.Time: 15 – 30 seconds, 2-4 timesType of activity: stretching exercises that focus on major joints.

Across –the-body and overhead stretches

Shoulders, upper back, back of arm

Upper-back stretch Upper backLateral stretch Trunk musclesStep stretch Hip, front of thighSide lunge Inner thigh, hip, calfInner thigh stretch Inner thigh, hipHip and trunk stretch Trunk, outer thigh, hip, buttocks,

lower backModified hurdler stretch Back of thigh, lower backAlternate leg stretcher Back of thigh, hip, knee, ankle,

buttocksLower-leg stretcher Calf, soleus, Achiles tendon

Remember…▫Improper stretching does more harm than good▫Understand the different types of stretching

exercises and how they affect muscles. ▫Do stretching exercises statically. ▫Do not stretch to the point of pain. ▫Relax and breathe easily as you stretch▫Perform all exercises on both sides of your body.▫Increase intensity and duration gradually over

time.▫Stretch when your muscles are warm

Preventing and managing lower-back pain•Back pain can result from sudden

traumatic injuries but it is more often the long-term result of weak and inflexible muscles, poor posture, or poor body mechanics during activities like lifting and carrying

•Any abnormal strain on the back can result in pain.

Function of the Spine• Provides structural support

for the body

• Surrounds and protects the spinal cord

• Supports much of the body’s weight and transmits it to the lower body

• Serves as an attachment site for a large number of muscles, tendons and ligaments

• Allows movement of the neck and back in all directions.

Structure of the Spine• Vertebrae

▫ Vertebral body: carries stress of body weight and physical activity

▫ Bony processes: joints to adjacent vertebrae and attachment sites for muscles and ligaments.

▫ Invertebral disks: absorb and disperse the stresses placed on the spine, separate vertebrae from each other.

Vertebral arch Vertebral

body

Invertebral disk

Nerve root

Structure of the Spine

• Vertebrae▫7 cervical▫12 thoracic▫5 lumbar▫Sacrum ▫Coccyx

• 4 curves▫Cervical▫Thoracic▫Lumbar▫Sacral

Core muscle fitness• Muscles in the abdomen, pelvic floor, sides of

the trunk, back, buttocks, hip and pelvis

• 29 muscles

• Stabilize the spine and help transfer force between the upper body and lower body

• During dynamic exercise, core muscles work together to produce movement and stability

• When specific core muscles are weak or tired, the nervous system steps in and uses other muscles producing abnormal stress on the joints, decreased power and an increase in the risk of injury.

Causes of back pain• Being greater than 34 years• Degenerative diseases such as arthritis or osteoporosis• Family or personal history of back pain or trauma• Sedentary lifestyle• Low job satisfaction• Low socioeconomic status• Smoking• Excess body weight• Psychological stress or depression• Physically hard work: frequent lifting, twisting, bending, standing up or straining in forced positions• High concentration demands (computer programming)• Vibrations (truck driving)

•Underlying causes▫Poor muscle endurance and strength

in the core muscles▫Excess body weight▫Poor posture and body position

when standing, sitting or sleeping▫Poor body mechanics when

performing actions like lifting and carrying or sports movements.

•Symptoms▫Numbness in the back, hip, leg or foot▫Radiating pain▫Loss of muscle function▫Depressed reflexes▫Muscle spasm

Preventing low back pain• Lose weight, stop smoking, reduce stress

• Avoid sitting, standing or working in the same position for too long.

• Use a supportive seat and a medium-firm mattress

• Use lumbar support when driving

• Warm up thoroughly before exercising

• Progress gradually when attempting to improve strength or fitness.

Managing back painAcute Chronic• Cold treatments• Heat treatments• Nonsteroidal anti-

inflammatory medication• Immediate rest following the

onset of back pain• Limit bed rest to one day

and begin moderate physical activity as soon as possible

• See your physician if acute back pain doesn’t resolve within a short time.

• Low-back pain is considered chronic if it persists for more than 3 months

• Prescription medications• Exercise• Physical therapy• Massage, yoga or

chiropractic care• Acupuncture• Percutaneous electrical

nerve stimulation• Psychological therapy

LAB ACTIVITIESLab 9.3 Lab 9.4• Assessing muscular

endurance for low back health

• Posture evaluation