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)

• Objectives of most fitness programs are to improve: – 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

– 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

• 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

Does this machine have variable resistanceor not?

•adv - safety, convenient to change wts, versatility in force direction, motivation

•disadv - cost, balance not required

• Concentric & eccrentric, agonists only

Resistive Exercise Equipment

• Variable resistance training devices (Fig 8.4. 8.5, p 252-253) – 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

ComputerizedExercise Machine

Concentric, Agonists & antagonists - Or agonists only

Isokinetic (accomodating) Resistance (one-way)

(concentric only, agonists only, oragonists & antagonists)

Pneumatic Resistance(air, two-way)

Concentric,Agonists & antagonists

Hydraulic Resistance

Two-way Resistance (concentric, agonists &antagonists)

Elastic Resistance

Bowflex: Soloflex:Concentric and eccentric contractions, agonists only

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?

Sample Flexibility Program

• 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?

Hamstring stretch

Anterior hip stretch (single leg lunge)

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

– 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?

Methods for Equipment Selection

• Apply relevant scientific principles to evaluate claims– 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?

• 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?

Exercise Equipment of Questionable Value

• 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

• 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 onhow you do it!

Abdominal Exercises:

When knees are straight, hipflexors initiate the situp movement by forward rotationof the pelvic, exaggerating theposterior lumbar curve.

Anchoring the feet enables hipflexors to contribute to the situp, lowering abdominal muscle activity.

What is the effect of the inclinedboard?