Transcript Fitness Applications: Introduction (1)

Fitness applications - objectives
• To develop a knowledge and understanding of:
• the role of biomechanics in fitness programing
• Fitness objectives and conditioning principles
• Biomechanics principles in the design and conduct of resistive,
aerobic, and flexibility exercise
• Design, evaluation, and selection of resistive and aerobic
exercise equipment
• Exercise and exercise equipment of questionable value
Fitness Applications: Introduction
• References (on reserve):
– Kreighbaum & Barthels (1996). Biomechanics: A qualitatibve approach
for studying human movement. Chapter 8 – pp 245-271
– Baechle (2000). Essentials of Strength Training and Conditioning. Ch 3
• Role of Biomechanics in Fitness Programming
– Anatomical-mechanical analyses of exercise design (What exercises to do?)
– Anatomical-mechanical analyses of exercises (Technique, or how to do it?)
– Mechanical analysis of exercise equipment (Design and selection)
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Objectives of most fitness programs are to improve:
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Muscular Strength
Skeletal strength
Muscular Endurance
Flexibility
Cardiorespiratory Endurance
General fitness conditioning
principles
• Important conditioning principles:
– Progressive overload
– Specificity of training – SAID principle
• movement pattern, joint position, speed, type of contraction
• Remember which aspect of fitness you are working
on and apply the overload and specificity principles
appropriately
• What is the stimulus for improvement of each
fitness element?
Biomechanics of Resistive exercises
• Factors affecting force
application
– Force-velocity relationship
– Strength-joint position
relationship (combination of
angle of pull and force/length
relationship)
• Should we provide the same
degree of overload
throughout the movement? If
so, how do we do it?
Use of Cams in Ex Equipment:
Why?
Recommended forearm flexion exercise –
Variable resistance, NATURALLY!
Recommended Extension Exercise –
variable resistance, NATURALLY!
Effect of speed on effects of exercise:
Torque = Wd + MOI x ang acc
Developing Muscular Strength
• Muscular Strength - ability of segment to exert force (MVC)
– Overload stimulus is tension
– Factors affecting force application:
• Force-velocity relationship
• Strength-joint position relationship (combination of angle of pull and force/length
relationship)
– Use load < 10 RM
– Focus on fundamental movements, antigravity musculature, and proportionate
development
– Specificity principle applies to:
• body position
• speed and type of contraction
– Concentric
– Eccentric
– Isometric
• Range of motion
• movement pattern
• pre-contraction stretch condition (plyometrics)
Developing Muscular Endurance
• Mucular Endurance- ability to repeat or sustain
submaximal contractions
– Overload stimulus is work intensity
– Use load approx 60% of max strength, or > 10 RM
– Focus on fundamental movements, antigravity musculature, and
proport.
– Specificity principle applies to resistance, body position, speed,
cadence, ROM, and total number of reps
• Cardiorespiratory Endurance - Aerobic capacity
– Overload stimulus is VO2 max, Cardiac output, or Heart Rate
– Repetition and resistance relative to muscular strength/endurance
are important
– Remember specificity principle regarding gravity, muscles
involved
Developing Skeletal Strength
• Overload stimulus is strain (normalized deformation )
• Remember 4 loading modes
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Compression
Tension
Torsion
Shear
• Exercise in gravitational environment and emphasize
resistive exercises
• Skeletal strength is developed concomitantly with
muscular strength development
• The best way to prevent osteoporosis is to build up bone
mineral content (BMC) during childhood, adolescence and
early adulthood
Developing Flexibility
• Flexibility - Joint ROM
– Soft tissues (collagen fibers) and musculotendinous unit must be
lengthened
– Overload stimulus is prolonged stretch (> 30 secs)
– Focus on these problem areas, apply PNF principles
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plantar flexors
hamstrings
lumbar spinal extensors
hip flexors
pectoral muscles
finger flexors
– Flexibility is specific to body segment
– Methods of stretching - slow, static; dynamic, PNF (CR, CRAC)
Understanding questions related
to biomechanics of fitness
• Devise a series of exercises for strengthening the triceps brachii.
Recall its functions at both joints, its three proximal attachments, its
possibility for length-tension adjustments, and its potential for active
and passive insufficiency.
• What is the overload stimulus for development of each of the
following fitness elements? (1) Muscular strength, (2) muscular
endurance, (3) flexibility, (4) bone strength, (5) cardiorespiratory
endurance.
• Name a flexibility test that you have taken in the past that is biased for
or against people with different body segment proportions.
• Why is the timed situp test with the feet anchored ill advised?
Resistive Exercise Equipment
• Simple and handy devices (plastic bottles, rubber tubing,
springs)
– adv - cheap, convenient
– disadv - no versatility in direction, force, speed
• Body weight – pushups, pullups, situps
– Adv – cheap, convenient
– Disadv – no versatility in direction, force, speed
• Free weights
– adv – convenient to use, cheap, balance necessary during lifts,
portable, inherent motivation
– disadv – safety (need a spotter, easy for beginners to do exercises
improperly), inconvenient to change wts, no versatility in
direction, speed
Gravity-dependent Weight Machine
•adv - safety,
convenient to change
wts, versatility in
force direction,
motivation
•disadv - cost,
balance not required
• Concentric &
eccrentric,
agonists only
Does this machine have
variable resistance
or not?
Resistive Exercise Equipment
• Variable resistance training devices (Fig 8.4. 8.5, p 252253)
– adv - variable resistance as well as direction of force app,
motivation
– disadv - cost, no versatility in speed
• Isokinetic devices (Fig 8.6, p 254)
– Adv - speed specific, vary force during movement (great for
rehab)
– Disadv - motivation, cost
• Computer-assisted devices (Fig 8.7. p 256)
– adv - variable resistance & speed, motivation, permanent record
– disadv - cost
Variable
Resistance
Weight Machine
Concentric & eccentric,
agonists only
Computerized
Exercise
Machine
Concentric, Agonists
& antagonists Or agonists only
Isokinetic (accomodating)
Resistance (one-way)
(concentric only,
agonists only, or
agonists &
antagonists)
Pneumatic Resistance
(air, two-way)
Concentric,
Agonists &
antagonists
Hydraulic
Resistance
Two-way
Resistance
(concentric,
agonists &
antagonists)
Elastic Resistance
Concentric and eccentric contractions, agonists only
Bowflex:
Soloflex:
Sample Resistive Exercise Program
• Basic Program - required
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Squat with heel raise
Trunk curl (goal is 30 reps)
Bench press
Sit or bent row
Upright press
Pull downs or chins
Optional exercises
– Back extension from prone position
– Forearm curl
– Forearm extension or dips
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Note: This program incorporates the principles of bilateral and agonisticantagonistic balance and focuses on muscular strength and endurance development
of the antigravity musculature. At least two sets (one with light weight for
warmup), and preferably three sets, of each exercise should be completed at 10-15
RM.
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What exercises would you change or add?
Sample Flexibility Program
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Slant board (calf stretch)
Single leg lunge (anterior hip stretch)
Lumbar stretch- sitting with knees bent, feet crossed
Hamstring stretch (touch toes or floor, knees straight)
Chicken wing (pectoral stretch)
Note: These exercises are selected to improve flexibility in
areas where most people have an inadequate amount of
flexibility. To enhance effectiveness, apply PNF principles.
• What exercises would you change or add?
Anterior hip stretch (single leg lunge)
Hamstring stretch
Understanding questions
• Explain why it is so important to do gravity-dependent resistive exercises slowly.
• Compare the difficulty of doing straight-leg situps with (a) the hands beside the
neck, (b) the arms crossed over the shoulders, and © the arms at the sides. Explain
the differences in difficulty in terms of motive and resistive torques and muscle
groups being used.
• Explain the difference between the elastic and plastic elongation of connective
tissue.
• Devise an exercise using the PNF procedure for extending the ROM for shoulder
girdle retraction and shoulder joint transverse extension.
• For each of the exercises shown in the
figure to the right, name the (a) joint
affected, (b)muscle group being
stretched, © source of the force used to
push or pull the joint beyond its range,
(d) muscle group antagonistic to the
group being stretched.
Which aerobic exercise mode is best?
• Equipment simulates some activities using large
proportion of total body musculature
• Exercise modes include walking, running, stairclimbing,
bicycling, rowing, skiing, swimming
• Discuss each mode relative to the following criteria
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Degree of overload on cardiorespiratory system
Relevance to fundamental movements and ADL’s
Proportion of total body musculature involved
Degree of compressive stress on femoral head and lumbar
vertebral bodies (sites of most osteoporotic fractures)
Compressive stress on patella and knee joint
Range of motion and torque at hip, knee, and lumbar spine
Motivational features (comfort, user friendly, feedback, RPE)
Likelihood of continued usage
Methods for Equipment Selection
• Apply relevant scientific principles to evaluate claims
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Biomechanical
Physiological
Psychological
Use it yourself at conferences or health clubs
• Product reviews in fitness magazines (Club Industry, Athletic
Business, Fitness Management)
• Try it yourself and take a tall or short person with you
• Consult with experts who supervise its use, or other professionals
(e.g., professors in area of expertise)
• Look at research available, if any
• Evaluate quality of research
– Who sponsored research?
– Peer-reviewed presentation?
Relevant Questions for Equipment Selection Criteria
• Can you apply specificity principles appropriately?
– Type of contraction, movement pattern, speed
– Carryover to living in gravitational environment?
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Is resistance enough to accomodate your strength?
Does it fit different sized people?
Is it safe?
Is it uncomplicated to use (user friendly)
Is there scientific evidence to support manufacturer’s claims?
Does the equipment follow a normal neuromuscular pattern?
If variable resistance, does resistance follow normal strengthposition curve?
• Does it have motivation-enhancing features?
Exercise Equipment of Questionable Value
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Devices to vibrate, melt, or massage away fat
Stretching, pulling, or pushing devices
Wearing or carrying weights
Rebounders or minitrampolines - Exerlopers
Healthrider
Healthstrider
Electrical stimulators
References:
– Burke, Edmund R. (1996) (Ed.) Complete Home Fitness
Handbook. Human Kinetics.
– Kreighbaum, E. & Barthels. (1996) Sports and Fitness Equipment
Design. Human Kinetics.
Questionable exercises
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Hyperextended back
Good morning exercise
Straight leg deadlift
Deep knee bends beyond thighs parallel
Ballistic rotation movements of spine
Behind neck press
Bouncing and jumping with one-legged landings
Questionable exercises:
It depends on
how you do it!
Abdominal
Exercises:
When knees are straight, hip
flexors initiate the situp
movement by forward rotation
of the pelvic, exaggerating the
posterior lumbar curve.
Anchoring the feet enables hip
flexors to contribute to the
situp, lowering abdominal
muscle activity.
What is the effect of the inclined
board?