Transcript RESISTANCE EXERCISE

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Resistance exercise is active exercise in which
muscle contraction is resisted by an outside
force. This outside force may be manual or
mechanical.
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Regular resistive exercise is associated with
several positive adaptations which is dosage
dependent.
These changes include:
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Acute adaptations are changes that occur in the
body during and shortly after an exercise bout.
Chronic adaptations are changes in the body
that occur after repeated training bouts and that
persist long after a training session is over
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Early strength gains are often attributed to so
called neural factors
It is believed to be the dominant influence in the
1st to 2nd month of a training program
Assumption from increased EMG amplitude
measured during maximal contractions
Co-contraction – refers to the simultaneous
activation of an agonist or antagonist during a
motor task
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Happen prior to structural changes
Increase in muscle recruitment (71% in untrained)
Increase in firing rate
Increase in the timing and discharge during high intensity muscular
contraction
Increase in hypertrophy
Lower activation threshold
Increase in inhibition of antagonist (via GTOs) The Golgi Tendon Organ
◦ § Cocontraction
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Increase in Neuromuscular Junction
Increase in Cross-education (Cross education is
a neurophysiological phenomenon where an increase in strength is witnessed within
an untrained limb following unilateral strength training in the opposite, contralateral
limb. Cross education can also be seen in the transfer of skills from one limb to the
other.
◦ § Up to 22%
◦ § Greater EMG
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Bilateral deficit(The bilateral deficit is a phenomenon where the total
force production of a bilateral lift (i.e. a squat, deadlift) will not be
greater than the sum of individual efforts of a single limb.
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Stretch Reflex
Increase in spindle fiber activity by 19-55%
Motor units are recruited according to their threshold of
firing rates
Larger loads, greater muscle fiber recruitment
The technique of recording electrical events
Electromyography EMG
The process of skeletal muscle activation involves
action potential generation on the muscle cell
membrane via acetylcholine release from the alpha
motor neuron that innervates a particular muscle cell
The action potential is manifested as a voltage change
on the sarcolemma that can be recorded with either
surface or intramuscular electrodes
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The primary adaptation of skeletal muscle to
long-term resistance training is hypertrophy, or
increased cross sectional area (CSA) of a muscle
fiber, resulting in increased force and power
production
During and immediately after resistance exercise,
metabolites accumulate and fuel substrates are
depleted; thus, clients need to include adequate
CHO in their diets
1. Increase in CSA
2. Due to in increase in synthesis and decrease in
degradation of contractile proteins
3. Increase in the number of myofibrils within a fiber
4. Resistance training can alter up to 70 different
genes
◦ § Increasing regeneration
◦ § Down regulation of inhibitory growth factors
5. Protein synthesis is increased up to 48 hrs
following RT
6. Depends on availability of Carb, Pro, and Kcal
◦ § As well as nutrient timing, cell hydration, and
mechanical stress of the RT
7. Fiber damage and disruption stimulate
synthesis as well
8. Increases are seen in both Type I and II fibers
◦ § Minimal in Type I
9. Athletes who generally possess a relatively
large proportion of Type II may have a greater
potential for increasing muscle mass with RT
10. We see a shift in fiber type due to RT
1. An increase in the number of fibers
◦ § Via longitudinal fiber splitting
◦ Hyperplasia is different from hypertrophy in that
the adaptive cell change in hypertrophy is an increase
in cell size, whereas hyperplasia involves an increase
in the number of cells.
2. Shown to occur in animals
3. Debated in humans
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Change in ATP and CP concentration seem to
be very sensitive to the training mode…
High volume resistance training may induce
glycolytic enzymatic adaptations that increase
muscle endurance
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Hormones are blood-borne molecules that are
produced ion the glands called the endocrine
glands.
Anabolic – stimulate growth
◦ ± Catabolic – tissue degradation to help maintain
homeostatis
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Osteoporosis – is the consequence of long-term
net demineralization of bone
The greater the bone mass prior to menopause,
the less severe are the consequences of loss of
bone mass. Resistance training may lead to
decreased risk for osteoporosis, fractures, and
falls in later life
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Osteoblasts
◦ New bone on Periosteum
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Osteoclasts
◦ Cells that break down bone
◦ Decreased activity decrease bone mineral density
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Stress is needed for bone to remodel
◦ Minimal Essential Strain
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RT causes deformation of specific skeletal
regions
Types of force from RT
◦ Bending, compressive, and or torsional
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Osteoblasts migrate to the area of stress
◦ Secrete proteins into the space between cells and
increase the bone matrix
◦ Sensitive to mechanical loading
◦ Increases diameter and strength of the bone
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The threshold for new bone growth must be met
by the force generated by RT
Increase in muscular strength and hypertrophy
cause and increase in force exerted on the bone
◦ Causing a direct correlation with Bone Mineral Density
BMD and muscular strength and hypertrophy
◦ Starts within first few sessions but is a long process
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Given the clear effect of resistance
training on Fat free mass (increase) and
its possible effects on resting muscle
metabolic rate, resistance training should
be a critical component of any
comprehensive program to control body
fat.
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Increase in Fat Free Mass (FFM)
Decrease in subcutaneous fat
Caloric intake and metabolism are factors
Cardiovascular exercise, Short term is more
effective in decreasing body fat
Specificity of loading should be used to target
specific sites
 Jumping will not cause a BMD increase in the
ulna
 The higher the impact the greater the BMD
increase will be
 Overload progression must be followed
To fast will cause stress fractures
 Ideal to increase peak bone mass in early adult
hood
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a. Intensity
b. Speed
c. Direction of force
d. Volume of force
Structural component of all is collagen fiber
◦ a. A protein
◦ b. Derived from parent protein procollegen from the
fibroblasts
Stimulus for growth is the mechanical forces
created during RT
◦ a. The degree of adaptation is proportional to the force
applied during RT
◦ b. Needs to exceed threshold of strain
Increases strength and load bearing by
◦ a. Increasing the junction between the tendon
or ligament and bone surface
◦ b. Increasing the strength of the body of
tendon or ligament
◦ c. Increasing the network of fascia within the
skeletal muscle
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Stronger muscle pulls with greater force on their
bony attachments causing in increase in bone
mass at the tendon bone junction
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Increase in collagen fibril diameter
A greater number of covalent cross links within
the hypertrophied fiber
An increase in the number of collagen fibrils
An increase in the packing density of collagen
fibrils
◦ RT increase tendon stiffness
 Only with heavy loads of 80% RM
Function
◦ Provide smooth joint articulating surface
◦ Act as shock absorption
◦ Aid in attachment of connective tissue
Does not have its own blood supply
◦ Gets nutrients through diffusion from synovial fluid
RT will increase the thickness of the cartilage
that experiences weight bearing
◦ The heavier the thicker
Resistance training with aerobic endurance training can
improve the ability of the heart, lungs, and circulatory
system to function under conditions of high pressure and
force productions
Acute (exercise)
 Increase in
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§ HR
§ SV
§Q
§ BP
Have seen peaks of 320/250 mmHg an 208 b/m during
high intensity RT
Chronic while RT
 Blunted increases in HR and BP
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Ventilation generally does not limit RT
At most moderately improved by RT
Unless RT is done as a circuit
◦ Ventilation levels are highest directly following the
performance of an exercise
◦ ± Some increases have been seen in tidal volume and
breathing frequency as well as ventilation
equivalent
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± Adding aerobic training to RT will decrease the
ultimate effects of RT
o Strength power and hypertrophy
± Most studies have shown no adverse effects
of adding RT to aerobic training
± With the combination of Aerobic and Anaerobic
the risk of overtraining is increased
1. Specificity
 2. Sex
 3. Age
 4. Genetics
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overtraining is a physical, behavioral, and
emotional condition that occurs when the volume
and intensity of an individual's exercise exceeds
their recovery capacity. They cease making
progress, and can even begin to
lose strength and fitness.
Overtraining is a common problem in weight
training, but it can also be experienced
by runners and other athletes.
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Plateau followed by a decrease of strength gains
Sleep disturbances
Decrease in lean body mass
Decreased appetite
A cold that doesn’t go away
Flu like symptoms
Loss of interest
Mood Changes
Excessive muscle soreness
Detraining refers to the bodily
effect experienced when one
takes an extended break from
regular, vigorous fitness training.
Fitness levels and muscle
mass can decline during a break
that lasts between two and four
weeks. While this sort of long-term
break may reduce current fitness
levels, it may also offer long-term
benefits if the person starts
retraining, allowing them to
achieve higher levels of fitness
than before detraining.
 Atrophy in the fast-twitch muscle
occurs faster