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Case Study: Movement
Dr. Bosak
EXSC 510: Advanced Exercise Physiology
Raekwon J. Parker
Liberty University
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Sara and Tanya, novice to resistance training, can expect significant muscular strength
and endurance adaptations in the first 6 to 8 weeks. Sara, training with Tommy, the
power/strength athlete, should focus on high-load, low-repetition exercises with adequate rest
periods to maximize muscular strength gains. Tanya, training with Jimmy, the endurance athlete,
should focus on moderate-load, high-repetition exercises with shorter rest periods to improve
muscular endurance. These adaptations will be achieved through progressive overload, proper
form, and consistent training adherence.
A discussion of contractile speed, neurons, and muscle fiber types. The speed of
contractile means the ability of a specific muscle to the contractile force or a shortening speed of
a contraction (Power et al, 2018). The velocity of a job done by a person is determined by the
muscle figure, which is activated by the neurological system. Neurons have a very important role
in the transmission of impulses, which are initiated from the brain going to muscle. Thus,
muscular contraction can be achieved. The contraction speed of a specific muscle is affected by
the type of neuron and the frequency of the nerve impulses that enter through it.
Contractile speed of muscle fiber types can be grouped into two main categories: slow-
twitch (Type I) and fast-twitch (Type II) fibers. Slow-twitch fibers have a low contractile speed
but have a high ability to sustain output for a long duration with little to no fatigue. Therefore,
these fibers are more suitable for tasks involving endurance over a longer period of time. On the
other hand, fast-twitch fibers have a fast twitch rate, which can produce more force per unit, but
tends to fatigue faster. Therefore, these fibers are more suited for activities involving high power
output over a short period of time.
The relationship between muscle fiber type, intensity and duration of exercise. The
absolute and relative proportions of slow-twitch and fast-twitch fiber types within an individual’s
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musculature have an influence on that person’s contraction velocity and performance across a
continuum of physical activities. Prolonged aerobic activities such as distance running and
cycling utilize predominantly slow-twitch fibers due to their relative resistance to fatigue.
Conversely, high-intensity, high-power, short-duration activities such as weightlifting and
running activate fast-twitch fibers due to their ability to contract at fast velocity and for relatively
short durations.
Muscle fiber type is mainly determined by evolutionary factors and people are born with
a certain proportion of slow-twitch to fast-twitch fibers. Training can lead to some adaptation in
the muscle fibers, but it cannot completely change muscle fiber type.One factor that determines
fiber type recruitment in the human body is the call demands and level of stress associated with a
given job. When doing low-intensity exercise, the slow-twitch fiber is recruited first, mainly
because it burns oxygen efficiency, and helps a person last longer. As the level of stress increases
during exercise, the nervous system initiates the recruitment of fast-twitch fibers to provide extra
force production. The sequential recruitment model allows the human body to delicately balance
energy expenditure and adapt to various demands of training. Adaptation is defined as changes in
the structure and function of a cell or organ system that results in improved ability to maintain
homeostasis during stressful conditions (Powers & Howley,2018).
Resistance training is working out against force and being provided resistance if possible
to help build muscles. There are all kinds of resistance workouts, some of them include but not
limited to free weights, machine weights, sleds that you pull, and so on. The type of resistance
training that Sara and Tanya are going to be different because they would have two different
trainers and they’re going to have two different styles of workout. Sara and Tanya will need to be
tested to see what weight they can handle lifting when lifting is not the correct way. Weights will
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also be set to how many reps and sets that each girl is going to need to do during the daily
workout. Now the trainers have to make sure that Tommy and Jimmy are able to keep the control
of the girls’ motion when they’re lifting so that they don’t get injured. The trainers have to make
sure they give Sara and Tanya the rest they need between their sets and change their work out
daily.
After 6-8 weeks, Sara and Tanya (identical twins who are participating in different
training programs) should feel different – at least that is the expectation. Sara, who trains with
Tommy (a power/strength athlete) should also notice a significant increase in the amount of
muscle mass, as her training includes more load/weight (70-93% of 1RM) and fewer repetitions
(3-8 reps). Her training program should be incorporating core compound exercises such as
squats, deadlifts and bench presses to aid her in muscular development but help with strength as
well.We would expect brain change to improve her performance via greater efficiency to
generate force, but it’s unlikely we’ll see a large increase in endurance. Tanya needs to do
exercises of moderate intensity (with more repetitions but shorter rest between sets) to get better
muscular endurance. She can do some bodyweight exercises, lighter resistance training, and do
some circuit-style exercises. Neural adaptations from strength training is a disinhibition of
inhibitory mechanisms and evolution of intra- and intermuscular coordination. Disinhibition has
the following: GTO is also called the Golgi tendon organ. A sensory receptor, located near the
myotendinous junction, responsible for a reflex inhibition of the muscle it supplies when it is
undergoing excessive tension, either from shortening or passive stretching. Renshaw cells,
inhibitory connecting neurons(interneuron) located in the spinal cord, that dampen the rate of
discharge of the alpha motor neuron, and prevent the muscular damage caused by tetanic
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contraction.Supraspinal inhibitory signals, conscious or unconscious inhibitory signals coming
from the brain. (Bompa & Buzzichelli, 2015)
Jimmy is an endurance athlete, and will be training Tanya. Endurance training is defined
as someone who can run or participate in athletic events for a prolonged period of time. Tanya
will target multiple joint and muscle systems in the body that are training at an accelerated rate.
Some extra workouts that can assist Tanya preparation for her work outs are training on the bike,
running and swimming to help the elevation of the cardio and endurance. Jimmy is able to create
a workout system that can super set the different systems of the machine to help with the
endurance. The changes that occur in the first six to eight weeks of endurance training are as
follows: changes in the size of the heart muscle, heart rate, amount of blood pumped out by the
heart during each heartbeat (stroke volume), blood pressure and blood volume (Murphy, N.d.).
The workouts that they do during that time and seeing how far the girls have come and
got to see what it is like to be lifting and they got a better sense of what lifting is and to view the
progress the girls have made from the time they first started coming to their workout routine and
seeing their progress as they train and become stronger and learn more and more. Tommy spends
just as much time there as Jimmy but Tommy would focus on the workout that would benefit his
type of training; the power/strength training workout routine is below for the one that Sara did.
4X5 squats at 85 % of her max
3X7 deadlift
5X5 military press at 87 % of her max
3X10 dumbbell triceps extension
4X3 bench press at 93% of her max
3X10 back extension
5X5 power clean at 87% of her max
3X10 dumbbell curls
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The endurance training workout routine that Jimmy did for Tanya:
30 minutes swimming laps
25 minutes cycling (end of workout)
10X10 body weight push ups
6X5 curls on machine
6X5 triceps extension on machine
4X30 seconds box jumps
3X7 power clean at 50% of her max
4X25 body squats
Following a period of 8-12 weeks: Sara explains that if someone trains their strength and
power on a consistent basis, it’s logical (and probable) that they will experience further muscular
hypertrophy and more neural changes that should improve expression of force. This will produce
reliable gains in explosive strength, in addition to the speed at which this strength exhibits
actions. The improved physiology will most likely lead to enhanced recruitment of motor units
causing a greater total power output.
Tanya’s muscles will respond to an endurance training regimen with a growth in their
ability to endure prolonged exertion, over the course of several weeks: her mitochondria and
capillaries will begin to grow until her muscles can endure more prolonged bouts of physical
exertion. Tanya’s training will perhaps hypertrophy her musculature.
To summarize, the training approaches that Sara and Tanya are undertaking will produce
different adaptations because of their unique aims. At the end of Sara’s power/strength training,
we expect to see an increase in the amount of muscle tissue she’s packing and the ability of those
muscles to make her lift whatever she’s lifting. After Tanya’s endurance training, we expect to
see an increase in her ability to resist feelings of exhaustion and sustain activity.
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References
Powers, S.K. and Howley, E. T. (2018) Exercise Physiology: Theory and application to
fitness and performance (10th Ed.). McGraw Hill
Raekwon J. Parker
