Flexibility is important to decrease injury risk and improve ability to meet goals. Inflexibility can lead to muscles becoming too long or short over time based on stresses placed on them. Proper flexibility requires balance between agonist muscles that provide motion and antagonist muscles that oppose it, keeping the joint in the right position. The muscle stretch reflex uses sensory neurons to detect changes in muscle length and send signals to motor neurons, causing muscles to contract or relax as needed.

1. FLEXIBILITY
WHY IS IT SO IMPORTANT?

2. INCREASE RISK FOR
INJURY
DECREASE ABILITY
TO ACHIEVE GOALS
WITHOUT ADEQUATE
FLEXIBILITY

3. TEXT
Inflexibility

4. DAVIS’ LAW
▸ soft tissue (like muscles) heal in
response to the stresses that
damaged them
▸ The Result
▸ muscles that are always elongated
get longer
▸ muscles that are always contracted
get shorter

5. Agonist: the muscle(s) that
provides the major force to
complete the movement
(also know as Prime Movers)
MUSCLE PAIRS
Antagonist: the muscle(s)
that act in opposition to the
agonist.

6. BALANCE
IMBALANCE
Agonist and Antagonist muscles are of appropriate length.
The joint is in the appropriate position.
One of the pairs is too long (weak) or too short (tight).
Inappropriate length puts the joint in the wrong position.

7. MUSCLE STRETCH REFLEX

8. TEXT
C.
D.
F.
H.
neurons
A.
J.
muscle
→
←
( B._____________ )1
Terms
1) contract or relax
2) excitatory or inhibitory
3) afferent or efferent
•sensory
•motor
•hamstring
•quadriceps
•patellar
•spinal
•spindle fiber
( E. ______________ impulse)3
( G._______________ )2
( K. ______________ )1
( I. ______________ impulse)3
M. Draw in the correct arrow.
Muscle Stretch
Reflex
Names:
_______________
_______________
_______________
L.
WORKSHEETSIDE1

9. TEXT