First Year Physiology

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First Year Physiology Semester B Lecture 4
Strength Training Strength training
programmes Types of training Training adaptations
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Athletic performance Bodybuilding Ageing
Rehabilitation Prolonged bed rest Space
flight Muscular disease
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To cause a physiological adaptation (i.e. an
increase in strength) the organism must be loaded
above its habitual level.
As a muscle / individual becomes stronger the
load must be increased to ensure that it is
still overloaded. This is the principal of
progressive overload.
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• Progressive overload
• Intensity (load)
• Duration (number of repetitions)
• Recovery
• Frequency (number of sets)
• Specificity

Specificity related to muscle groups and muscle
action employed during sports performance.
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RM Repetition maximum 10 RM 10 repetition
maximum, the load that can just be lifted
10 times.
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Maximum force 100 1 RM
- the load that can just be lifted once.
10 RM 70 max force.
The optimal loading for strength training is
above 70 of max force, thats 10 RM or less.
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Repetitions - Sets - Rest e.g. BP 3 sets of 8
reps _at_ 70 kg with 3 mins rest.
3 - 4 sets per exercise is typical, with 2-3 mins
rest between sets.
2 - 3 training sessions per week is sufficient
for a significant increase in strength after 2-3
weeks, although a significant increase in muscle
size takes longer (8-15 weeks).
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Hypertrophy - an increase in the size (CSA) of
the muscle fibres that results in more
cross-bridges in parallel.
Neural adaptations - change in the activation of
the relevant muscles by the CNS.
Including (a) Increased activation signal to
the agonist and stabilizers. (b)
Decreased activation to the antagonist.
Increased amounts and strength of connective
tendinous and ligamentous tissue
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Hypertrophy - an increase in the size (CSA) of
the myofibrils resulting in more cross bridges
in parallel Hypertrophy vs hyperplasia ? Both
Ft and St fibres increase in diameter Heavy
resistance - low reps Training primary Ft
fibres Low resistance - high reps Both St and
Ft increase However only high forces (gt70 1RM)
induce significant hypertrophy
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Strength training adaptations tend to be very
specific to the training exercises
Length specificity adaptation of the muscles
to the length, joint positions and range of
motion of an exercise.
Action specificity adaptation of the muscle to
the type of action i.e. eccentric, concentric.
? Velocity specificity adaptation of the muscle
to the speed of contraction.
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Delayed-onset muscle soreness

• Muscle soreness felt 24 to 48 hours after heavy
  exercise
• Reduces force generating capacity of effected
  muscle
• Eccentric muscle action is the primary initiator

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It is important to maintain this natural
curvature of the spine, whatever lifts and
exercises are being performed.
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Vertebrae
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Strong abdominals protect the spine
IAP Intra-abdominal pressure
When the abdominals contract the abdomen acts as
a rigid block and takes some of the load off
the spine.
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Machine weights
Free weights
Advantages
Disadvantages
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Machine weights
Free weights
Prime movers and fixators Adaptable and specific
Compact Accessible Safe
Advantages
Need spotters Requires instruction
Disadvantages
Non - specific Prime movers only
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Electromyostimulation
Means of training by electrically stimulating
the muscles
Investigated in the 70s and 80s in the soviet
Union (Elson 1974, Moreno-Aranda et al 1981)
Rational Individuals are unable to activate a
muscle maximally and that electrical shocks
can stimulate the difference between what an
individual can activate and what is available
in the muscle. ? Over optimal voltage -
suggested to be just below
pain threshold
Not currently used due to ethical reasons /
discomfort to athletes
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Age and gender in strength training
The relative gains in strength seem to be
similar for men and women, but women do not
experience as much hypertrophy.
Older people improve in strength more slowly
than young adults. However CSA still
demonstrated in older people.
Children do adapt to strength training, but
slower than adults. No known detrimental
effect of strength training for children - in
terms of motor performance, skeletal growth or
flexibility (Rians et al., 1987).
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Strength and ageing Asmussen et al., 1980
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In older women strength training counteracts
the loss of bone mineral density and may reduce
risk of osteoporosis (Hartard, 1996).
Strength training may increase BMR more than
endurance training. This has implications for
weight loss. However, weight loss will not be
as good as continuous exercise due to its
intermittent nature
Psychological benefits in depression. Positive
changes in mood and vigour.
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Reading
Wilmore, JH and Costill, DL (1999) Physiology of
sport and exercise, 2nd edition. Human Kinetics,
Champaign, USA. Chapter 3 study questions
1 to 10 and Chapter 17 pages 557 - 560
Chapter 18 pages neuromuscular responses 576
577 pages neuromuscular adaptations 582 - 584