Transcript Biom/Phys Considerations for Fit Equip

Which aerobic exercise mode is
best?
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Compare each mode relative to the following criteria
- Degree of overload on cardiorespiratory system (Consumer
Reports Mar 2002, p 13)(Fitness Management August 2000,
p 1-3)
- 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?
Comparison of Aerobic Ex Modes:
HR while exercising at similar RPE
Comparison of Aerobic Ex Modes:
VO2 while exercising at similar RPE
Comparison of Aerobic Ex Modes:
Vertical Ground Reaction Force
Comparison
of Aerobic
Ex Modes:
How long does it
take to burn 200
calories?
Consumer Rep
March 2002, p
13, citing data
from MSSE
August, 2001.
19 subjects
exercising at
similar RPE’s
Comparison of Health Rider
and Treadmill on VO2 Max
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From website:
http://www.isu.edu/departments/dpot/research
/healthrider.html
Methods:
- Max ex bouts on each exercise type
- 15 college males & 15 college females
- Measured several variables indicative of overload
on cardioresp system
- VO2, VE, RER, Resp Rate, METS, HR, ratio of
VO2/HR
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Results:
- Treadmill produced superior results for all
variables, including VO2 max (53.8 ml/kg/min vs
38.1 ml/kg/min)
Approximate Cost of Aerobic
Exercise Equip at Rec Complex
Rowers
$1,000
 Stationary Bikes (upright & recumb) $2500
 Elliptical exercisers
$3200
 SciFit Total Body Crosstrainer
$4000
 Stairstepping machines
$4500
 Hybrid – Cybex Arctrainer
$5000
 Treadmills
$5000-$8000
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Cross-country ski simulators
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Advantages
-
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Potential for high energy expenditure
Good off-season training for skiing competition
Can talk or listen or watch
Non-impact
Disadvantages
- Not easy to learn to use
- Need to develop skill
- None have capability to convert exercise effort into
repeatable intensity
- Most models have poor feedback on work
intensity
Stationary cycles
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Advantages
-
Inexpensive, compact, portable
Can listen, talk, and watch
No heel-strike forces (.6 g)
Good feedback on work rate and energy
expenditure
- Easy to use
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Disadvantages
- Sore butt can be a problem
- Boring
- Only works the legs – those with poorly
conditioned leg muscles will fatigue quickly
- Low carryover to ADL’s
- Higher RPE than treadmill or ellipticals
Treadmills
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Advantages
- Good carryover to locomotion
- Can get good aerobic overload
- Can control speed and slope and can be
programmable and reproducible
- Weight bearing – high GRF’s
- Easy to learn how to use
- Greatest incidence of use in homes
- Lower RPE than most other aerobic ex machines
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Disadvantages
- Expensive
- Impacts and high VGRF may exacerbate lower
extremity problems
- Not portable and compact
- Noisy
Hybrid: Elliptical Exercisers
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Advantages
-
Can get good aerobic overload
Cheaper than treadmills & stepping machines
Lower RPE for same workout intensity
Low impact – less stress on lower extremities while allowing
a weight-bearing exercise
- Easy and safe to use
- No motor- less noisy than treadmills
- Can control speed and slope and can be programmable and
reproducible
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Disadvantages
- Low impact and lower VGRF than treadmills
- Movement is less similar to normal locomotion pattern than
treadmills
- Many models do not allow sufficient stride length for taller
people
Rowing machines
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Advantages
-
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Uses large muscle mass than cycling
Greater energy energy expenditure than cycling
Can talk or listen or watch
Non-impact
Cheap
Easy to learn how to use
Disadvantages
- Limited capability for incrementing and
reproducing workload
- Untrained rowers may fatigue quickly
- Low carryover to ADL
Stepping machines
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Advantages
-
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Low impact
Can talk or listen or watch
Easy to learn how to use
Relatively inexpensive
Disadvantages
- High knee torque and patellar compressive forces
(hard on knees)
- Minimal trunk and upper body involvement
- Can be boring
Exercise Equip of Questionable Value
Devices which purport to provide great benefits
with little effort
 Devices to vibrate, melt, or massage away fat
 Stretching, pulling, or pushing devices
 Wearing or carrying weights
 Others that you can think of?
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Other websites on exercise
equipment
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Source for exercise equipment:
- Fitnessquest home page
- http://www.exerlopers.com/
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Sites including exercise equipment
research :
- ISU Dept of OT
- Precor research page
- Sportscience journal
Methods for Resistive Equipment
Selection
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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 Resistive Equipment
Selection (Criteria)
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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
strength-position curve?
Does it have motivation-enhancing features?
Resistive Exercise Equipment
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Simple and handy devices (plastic bottles, rubber
tubing, springs)
- adv - cheap, convenient
- disadv - no versatility in direction, force, speed
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Constant resistance training devices (free wts, body
wt)
- adv – convenient to use, cheap, balance needed, portable,
motivation
- disadv - safety, inconvenient to change wts, no versatility
indirection, speed
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Gravity-dependent resistance machines (circular
pulleys)
- adv - safety, convenient to change wts, versatility in force
direction, motivation
- disadv - cost, balance not required
Gravity-dependent Resistance Wt
Machine
Concentric and
eccentric
contraction of
agonists only!
Resistive Equipment (cont’d)
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Variable resistance wt machine (CAMS or roller on
bar)
- adv - variable resistance as well as direction of force app,
motivation
- disadv - cost, no versatility in speed
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Isokinetic devices (same speed)
- Adv - speed specific, vary force during movement (great
for rehab)
- Disadv – most devices involve only concentric
contractions, motivation, cost
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Computer-assisted devices (can control either speed
or resistance)
- adv - variable resistance & speed, motivation, permanent
record
- disadv - cost
Variable
Resistance
Weight Machine
Concentric and eccentric
contraction of agonists only!
Computerized
Exercise
Machine
Agonists and
antagonists Concentric
contraction only!
Pneumatic Resistance
(air, two-way)
Agonists
and
antagonists
Concentric
contraction
only!
Isokinetic (accomodating)
Resistance (one-way)
Agonists
concentric
contraction only!
Hydraulic
Resistance
Agonists and
antagonists
Concentric
contraction
only!
Elastic Resistance
Agonists only, concentric & eccentric contraction
Bowflex:
Soloflex:
Exercise Equipment of Questionable
Value
Devices to vibrate, melt, or massage away fat
 Stretching, pulling, or pushing devices
 Wearing or carrying weights
 Evaluation of several types of ex equip:
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American Council on Exercise Research Page
Fitness Equipment: Index
Exerlopers Fitness Systems - Home Page
Electrical Muscle Stimulator
Source for purchasing exercise equipment:
- Fitnessquest home page
Approximate Costs of Resistive Ex
Equip
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Free weights
- Benches $660; dumbbell set $1,300; Rack for
dumbbells $585; Olumpic weight set $1,650
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Plate loaded weight machines - $1,500-$1,700
VRI station (variable resistance one axis) $1,700-$3,900
VRII station (variable resistance, 2 axes) - $2,300$4,000
Isokinetic (accomodating resistance) - $10,000
Computer-controlled - $20,000