NASM essentials of sports performance training
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NASM essentials of sports performance training

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integrating speed, strength, and power of an athlete (16\u201320).
Specific exercises can increase power output and explosiveness by training muscles to do more work
in a shorter amount of time (17,21\u201324). This occurs by utilizing the stretch-shortening cycle, which
occurs when an activated muscle transitions from an eccentric contraction (deceleration) to a rapid
concentric contraction (acceleration) (25\u201328). The rapid eccentric contraction creates a stretch reflex
storing potential energy that is used to produce a concentric contraction more forceful than could
otherwise be generated by the resting muscle (17,29). The shorter the amount of time between the
eccentric and the concentric contraction, the greater the potential energy stored and used for a more
concentric force production (16,25\u201327,30,31). Stabilization strength, core strength, and neuromus-
cular efficiency may help to control the time between the eccentric and the concentric contraction
(1). When eccentric strength, neuromuscular efficiency, and stabilization strength are optimized,
your athletes will realize greater concentric force production without an increase in hypertrophy
(morphological changes) (15\u201317,32,33). After you fully understand this concept, you will advise
your athletes to make use of exercises that maximize the stretch-shortening cycle that will make up a
larger portion of your athlete\u2019s integrated sports performance program (8,14\u201317,32,34\u201336).
Most strength and conditioning programs focus on isolated, uniplanar exercises to maximize ab-
solute strength gains and hypertrophy. However, the central nervous system (CNS) is designed to
optimize the selection of muscle synergies to perform integrated movement patterns in all three
planes of motion (4,7,9\u201311). Therefore, if the human movement system is designed to move in
all three planes of motion as an interdependent unit, isolated training does little to improve over-
all athletic performance. The athlete who applies an integrated functional approach to training
will develop high levels of dynamic flexibility, core strength, neuromuscular control, power,
speed/agility/quickness, and functional strength (14\u201317,32\u201336,38\u201347). In addition, your athlete
may develop similar, or even greater, levels of hypertrophy following improved motor unit re-
cruitment. Training that exploits integrated, functional movement patterns targets synergistic
muscles to regulate isometric, concentric, and eccentric force while dynamically stabilizing the
entire human movement system in all three planes of motion. This creates maximal motor unit
recruitment and facilitates a greater overall training response (44,47).
Every athletic activity occurs in all three planes of motion (Fig. 1.1): sagittal, frontal (or coronal),
and transverse (5,7,8,10\u201313). The majority of traditional strength and conditioning exercises occur
in the sagittal plane with the primary emphasis on concentric force production. An athletic activity
may appear to be dominant in one plane (e.g., sprinting), but movements in the other two planes of
motion must be controlled for effective performance (8,9,11). If a muscle is dominant in primarily
one plane (e.g., gluteus medius in the frontal plane, quadriceps in the sagittal plane, and external
obliques in the transverse plane), then you must develop a multiplanar training program. Only then
will you be able to efficiently and effectively prepare your athletes for their athletic activities and in-
jury prevention because many athletic injuries occur in the frontal and transverse plane
(7,8,10,12,15,48,49). Training only in the sagittal plane will not effectively prepare your athlete\u2019s
muscles that are dominant in the frontal and transverse plane (8,9,50,51).
Posture is a dynamic controlling quality. Optimum alignment of each segment of the human
movement system is a cornerstone to any functional sports performance program. If one
component of the human movement system is out of alignment, other components will have
An active stretch (eccentric con-
traction) of a muscle followed
by an immediate shortening
(concentric contraction) of that
same muscle.
Functional Strength
The ability of the neuro-
muscular system to contract ec-
centrically, isometrically and
concentrically in all three planes
of motion.
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to compensate for decreasing neuromuscular efficiency, which increases the chance of injury
(2,3,8,9,13,48,49,52\u201360). Poor posture during training can lead to muscle imbalances, joint
dysfunctions, and impairment of human movement (60). 
Training with proper posture ensures optimum results and decreases the risk of developing
muscle imbalances, joint dysfunctions, and tissue overload (Fig. 1.2). Allowing an athlete to per-
form exercises with poor lumbar posture may result in the development of muscle imbalances
FIGURE 1.1 Planes of motion. (From Cohen BJ. Memmler\u2019s The Human Body in Health and Disease, 10th edition.
Baltimore: Lippincott Williams & Wilkins; 2007.)
FIGURE 1.2 Training with optimum
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and possible injury (4,43,58,59,61). A functional, integrated training program of the entire hu-
man movement system ensures maintenance of structural integrity while requiring your athlete
to perform exercises correctly with proper postural control.
Muscles function optimally from an ideal predetermined length, thus an optimum length-
tension relationship (5). The muscle\u2019s length-tension relationship is altered when a muscle is
stimulated at a length less than or greater than this optimal length effectively altering force-
couple relationships and joint kinematics (3,56,60). Subtle changes in posture, pattern overload,
injury, and decreased neuromuscular efficiency can alter the resting length of muscle that can
lead to muscle imbalances. Muscle overactivity, adaptive muscle shortening or both can cause al-
tered reciprocal inhibition and synergistic dominance (2,8,9,54\u201356,62\u201364). Altered reciprocal
inhibition results in decreased force production by the prime mover and leads to compensation
by the synergists (synergistic dominance) (2,65). Synergistic dominance leads to altered move-
ment patterns and decreased neuromuscular control (2,7,8,12,55,60). Therefore, all sports per-
formance programs should be well planned and executed to ensure the development of opti-
mum muscle balance. In turn, this will ensure maintenance of the structural integrity of the
entire human movement system.
It is imperative that today\u2019s Sports Performance Professional understands human movement sci-
ence. The greater your understanding of human movement science, the more effective the per-
formance enhancement and injury prevention programs you design will be. As mentioned
before, muscles function eccentrically, isometrically, and concentrically in all three planes of mo-
tion (5). Movement is a complex event orchestrated by the CNS. The CNS executes pre-pro-
grammed patterns of movements that can be modified in response to gravity, ground reaction
forces, and momentum that must be trained accordingly. For example, CNS control allows the
gluteus maximus to work eccentrically to decelerate hip flexion, internal rotation, adduction, and
tibial internal rotation (through its attachment to the iliotibial band), isometrically to stabilize the
SI joint, and concentrically to extend and externally rotate the hip (5). The typical way to
strengthen the gluteus maximus is to have the athlete perform sagittal plane hip flexion/exten-