Topic 6- Muscular Strength and Endurance

Male differences that affect muscular strength + endurance

• increased testosterone

• larger bones

• increased muscle mass

Female differences that affect muscular strength + endurance

• increased estrogen

• widening differences of pelvis

• breast development

• higher fat in hips and thighs

Even when the training the same, females have a lower __ than males

VO2 max

Magnitude of difference in VO2 max between men/women in non-athletes vs athletes

Non-athletes- 25%

Elite athletes- 8-12%

Magnitude of difference in muscle strength between men/women in upper body/lower body

Upper body- 50% diff

Lower body- 30% diff

Starting at 30 years old, what happens to aerobic fitness?

It declines about 10% each decade (whether inactive or active)

From 20-90, what happens to muscle mass?

50% is lost

The loss in muscle mass that comes with age can be reduced by __?

training

law of use/disuse

If you don’t use it you lose it

atrophy

loss of muscle mass

hypertrophy

gain muscle mass

What does resistance training increase?

muscle mass/strength/endurance, metabolic rate, bone density, “antigravity/postural” muscles

What does resistance training improve?

balance, mobility, reaction time, sleep, combats depression, self-esteem, insulin sensitivity, weight loss/management, HDLs (not guaranteed)

What type of exercise best improves VO2 max?

aerobic

What type of exercise best improves bone density?

resistance

What type of exercise best improves physical function in old age?

resistance

Risk factors of lower back pain

unusual mechanical stress= excess body weight around abs, weak abs or hamstrings, poor posture, smoking (reduces blood flow), lifting objects incorrectly, work/sports injury, osteoporosis

osteoporosis

decreased bone density

Healthy vertebrae have

space between them (discs)

If there are no discs in between vertebrae, what happens?

pinched nerves

What kind of curvature is normal for a spine?

S shape

What part of the spine is responsible for the majority of back pain?

Lumbar (lower third)

How to prevent back pain

increase ab strength, increase hip/hamstring flexibility, proper lifting techniques (BLT), lose weight, better posture

BLT

when lifting: bend, lift, and no twisting

What can be the best exercise to prevent back problems and why?

partial curl-up (feet free) because it has high activity in ab muscles, decreases lumbar compression, and avoids using the hip flexor

How does muscle attach to bone?

tendons

What is a muscle made up of?

Fasiculus and fibers

Types of muscle fibers

actin and myosin

Sarcomere

functional unit of muscle- where muscle contraction occurs

Muscle components

muscle → fasiculus → fibers → myofibrils → myofiliaments

Two types of myofilaments

actin and myosin

neuromuscular junction

where nerves connect to the muscle

motor unit

nerve and all muscle fibers that it communicates with

With strength training, what is the order of physical change?

Neural changes first, then hypertrophy

Hypertrophy increases:

• size/# of myofibrils

• total muscle protein

• amount/strength of connective/tendon/ligament tissues

• # of muscle cells (small increase)

• fast twitch

Other changes that occur with strength training

• increases lean mass

• small increase in VO2 with circuit training

• increases left ventricle wall thickness (which increases PVR and BP)

How quickly does improvement occur with strength training?

• 25-30% strength improvement in first 6 months

• significant hypertrophy in the first 2 months

3 principles of weight training

overload, progressive resistance, and specificity

ACSM resistance training guidelines

• 8-10 exercises for whole body

• 2-4 sets, 8-12 reps, 60-80% 1 RM

• 2-4 days/week

ACSM tips for resistance training

• focus on technique

• breathe normally

• training partner

• opposing muscle groups

• 2-3 min rest between sets

• 48 hours between sessions

For optimal strength gains, what frequency for spine workouts?

1-2 days/week

For optimal strength gains, what frequency for appendicular skeleton workouts?

3 days/week

Appendicular skeleton

arms and legs

5 variables of weight lifting

1. reps

2. sets

3. rest between sets

4. order of exercises

5. type of exercise

Strength vs endurance- number of reps

Strength < 10 (3-5) with high weight

Endurance > 10 (15-25) with low weight

Ways of determining intensity in resistance training

1. AMRAP

2. 1 rep max

3. RPE

4. repetitions in reserve

% 1 RM for endurance

< 67%

% 1 RM for hypertrophy

67-85%

% 1 RM for strength

>85%

% 1 RM for power

0-95% (depends on exercise)

How to determine number of sets?

1 for beginners, 3-5 for everyone else

For endurance, how much rest is needed between sets?

30 sec-1 min

For hypertrophy, how much rest is needed between sets?

90 sec-3 min

For strength/power, how much rest is needed between sets?

2-5 min

Typical rest between sets

1-2 min

Order of exercises

large muscle groups before small, multiple joints before single joints

Isometric contractions

• no movement

• specific to angle

• max gains 5-10 reps, 6 sec holds at 100% max volume contraction, repeated at 3 points

• cheap and convenient but significant increase in BP

MVC or MVIC

max volume contraction

Isotonic contraction

• constant resistance

• concentric & eccentric phases

Concentric phase

muscle shortens

Eccentric phase

muscle lengthens (40% greater force than concentric but with no greater increase in strength)

Eccentric phase is associated with

increased DOMS

Isokinetic contraction

• Biodex & KinCom machines

• adjusts speed to apply constant force

• muscle applies max tension during entire lift

In a biodex machine, when speed increases, force ___ and why?

decreases, because there’s less time to recruit/synchronize motor units

Pros of isotonic contraction

it’s self-testing (you decide how much you want to lift)

Pros/cons of isometric & isokinetic contractions

Isometric doesn’t need lots of equipment, isokinetic needs lots of it and it’s finicky and expensive (though it leads to better results)

Is there an absolute strength difference between men and women?

No, when it’s expressed per unit of muscle cross section (linear relationship)

ACSM muscle strength recommendations- muscle action

isotonic, supramaximal eccentric exercises

ACSM muscle strength recommendations- load

novice- 60-70% 1 RM, 8-12 reps

advanced- 80-100% periodized 1 RM, 1-12 reps

ACSM muscle strength recommendations- volume

novice- 1-3 sets, advanced- multiple periodized sets

ACSM muscle strength recommendations- exercises

multiple & single joint exercises

ACSM muscle strength recommendations- order

large before small, multiple before single joints, work the whole body

ACSM muscle strength recommendations- rest

2-3 minutes for multiple, 1-2 min for single

ACSM muscle strength recommendations- speed

novice- slow to moderate, intermediate- moderate, advanced- advanced continuum slow to fast

ACSM muscle strength recommendations- frequency

novice- 2-3 days/week, intermediate 2-4, advanced 4-6, sometimes 2 workouts a day