Transcript Fitness Applications: Introduction (1)

Fitness applications - objectives
• To develop a knowledge and understanding of:
• The role of biomechanics in fitness programming
• 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
• Exercises 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!
Effect of speed on torque during exercise:
Torque = Wd + MOI x ang acc
Recommended Extension Exercise –
variable resistance, NATURALLY!
Effect of speed on torque during exercise:
Torque = Wd + MOI x ang acc
Developing Muscular Strength
• Muscular Strength - ability of segment to exert force (MVC)
– Overload stimulus is tension (use resistance equal to or greater than 10 RM )
– Factors affecting force application:
• Force-velocity relationship
• Strength-joint position relationship (combination of angle of pull and force/length
relationship)
– 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
proportionate development
– 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
weight bearing and 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
Sample Resistive Exercise Program
• Basic Program - required
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Bench press
Sit or bent row
Upright press
Pull downs or chins
Squat with heel raise
Trunk curl (goal is 30 reps)
Optional exercises
Back extension from prone position
Forearm curl
Forearm extension or dips
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?
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.
• Explain two ways that resistance changes during the movement of a
gravity-dependent exercise using free weights or the body as the
resistance.
• What is a variable resistance exercise machine? What is the reason
for their design and use?
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.
• 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:
Relevant Questions for, or Criteria, for Resistive
Exercise Equipment Selection
• Can you apply specificity principles appropriately?
– Type of contraction, movement pattern, speed
– Carryover to living in gravitational environment?
• Is there scientific evidence to support manufacturer’s claims?
• Does the exercise using the equipment follow a normal
neuromuscular pattern?
• Does the exercise using the equipment involve both eccentric and
concentric muscle contractions?
• If variable resistance, does resistance follow normal strengthposition curve?
• Does it have motivation-enhancing features? Such as:
– Control and feedback on work load or resistance
– Relatively low ratings of perceived exertion
Relevant Questions for, or Criteria, for Aerobic
Exercise Equipment Selection
• Equipment simulates some activities using large proportion of total body
musculature
• Exercise modes include walking, running, stair climbing, bicycling, rowing, skiing,
swimming
• Evaluate each mode relative to the following criteria
– 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
– Cost
– Other?
Analysis 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?
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?