Scientific Bases for Evaluation of Fitness Equipment

 Reading assignment: Read Ch 11 of text; Baechle; Ch 3; Kreighbaum 2; pp 257-265; Adrian, pp 221-225  Homework (due Thursday, October 6) Submit 2 questions or concerns from readings on scientific foundations for fitness equipment for discussion

Scientific Considerations for Fit Equip

 

Objectives of most fitness programs are to improve

: Musc strength, musc endurance, C-V end, weight control,

skeletal, or bone fitness,

& flexibility

Important conditioning principles:

Progressive overload Specificity of training • SAID principle applies to the following – Cellular demands, systemic demands evoke specific responses resulting in performance (functional) and tissue (structural) adaptations • Specificity applies to many aspects of the training program, including – Muscle groups, energy system, body position, environmental conditions, movement pattern, joint position, speed, type of contraction  

What is stimulus for improvement of each fitness element

?

What is the context in which adaptation/improvement is most desirable?

Biom/Phys Considerations for Fit Equip



Remember which aspect of fitness you are working on and apply the overload and specificity principles appropriately



Muscular Strength - ability of segment to exert force (MVC

) Overload stimulus is

tension, so use load <10RM

Factors affecting force application: • • Force-velocity relationship (see slide later) Strength-joint position relationship (combination of angle of pull and force/length relationship) (slide later) Focus on • • • fundamental movements – why and what are they antigravity musculature – why and what?

proportionate development – what’s that?

Specificity principle applies to body position, speed (type of contraction), ROM, pre-contraction stretch condition, and movement pattern )

Biom/Phys Considerations for Fit Equip

   

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

VO 2 max, Cardiac output, or Heart Rate

Repetition and resistance relative to muscular strength/endurance are important Remember specificity principle regarding gravity, muscles involved

Bone, or skeletal, fitness

Overload stimulus is

strain

(normalized deformation ) • Remember 4 loading modes (compression, tension, torsion, shear) • Exercise in gravitational environment and emphasize resistive exercises

Flexibility – stretching exercises are not equipment intensive



Bone Response to Stress

Wolf’s Law Indicates that bone strength increases and decreases as the functional forces on the bone increase and decrease.

 Bone Modeling/Remodeling Mechanical loading causes

strain

If

strain

is greater than modeling threshold, then bone modeling occurs.

If

strain

is less than lower remodeling threshold, then bone remodeling occurs.

 Osteogenic effect of exercise regimen depends on: Magnitude of load (if weight bearing exercise, use BW ratio) Cycles, or repetitions per exercise bout (e.g., # of steps per leg) Number of sessions per week Loading rate

Position Statement of ACSM on Osteoporosis



Weight bearing

physical activity is essential for developing and maintaining a healthy skeleton 

Resistive

exercises may also be beneficial, particularly for non-weightbearing bones  An increase in physical activity for sedentary women can prevent further inactivity-related bone loss and can even improve bone mass  Exercise is not an adequate substitute for postmenopausal hormone replacement, or pharmacological agents  Ex programs for older women should include activities for improving strength, flexibility, and coordination, to lessen the likelihood of falls

Force-velocity Relationship:

Strength Position Curves:

Resistance-Position Relationship:

Remember T = WD + I



When is acceleration positive?

Zero?

Negative?

Use of Cams in Ex Equipment:

Sample Resistive Exercise Program    

Basic Program - required

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

Note:

This program incorporates the principles of bilateral and agonistic antagonistic 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.

What exercises would you change or add?

Questionable exercises

 Hyperextended back  Good morning exercise  Straight leg deadlift  Deep knee bends beyond thighs parallel  Behind neck press  Unsafe abdominal exercises

Spine loading – one big leg (disc and vertebral body), two smaller legs (facet) in rear. Balance the load

Questionable exercises:

Hyperextended back “Good morning” exercise

Straight-legged Deadlift:

Squats: It depends on how you do it!

Behind the neck press :

Situp Exercises:

Which methods are Potentially harmful?

In what way?