EXS 387 - Biomechanics Lab #2b

Lab time: ___________________________
Name: _____________________________
EXS 387 - Biomechanics
Lab #2b - ANATOMICAL ANALYSIS OF MOVEMENT
Learning objective: Identify the muscles active during each phase of a human movement.
Analysis procedures:
1. Identify the joint action.
2. Identify the type of muscle contraction (concentric, eccentric, or isometric).
a. Determine if the mechanical energy of the limbs and body increase (speeding up or lifting), decrease
(slowing down or lowering), or don't change (no movement at joint).
b. The change in energy indicates the total work done (positive, negative, or zero).
c. If no external forces other than gravity act on the limbs and body, then the muscle action is:
• concentric if positive work is done
• eccentric if negative work is done
• isometric or no action at all if zero work is done.
d. If external forces other than gravity do act on the limbs and body, then imagine what would happen at
the joint if no muscle contractions occurred:
• if the imagined joint action is the same as the joint action observed but faster, then the muscle
action is eccentric.
• if the imagined joint action is opposite to the joint action observed, then the muscle action is
concentric.
• if no joint action was observed, but there is imagined joint action, then the muscle action is
isometric and the active muscle group is an antagonist to the imagined joint action.
3. Identify the role of the active muscle group.
a. If the muscle action is concentric - the active muscles are agonists to the joint action.
b. If the muscle action is eccentric - the active muscles are antagonists to the joint action.
c. If the muscle action is isometric - the active muscles are stabilizers.
4. Identify the active muscle group.
a. If the active muscles are agonists to the joint action - the muscles produce a torque in the same
direction as the joint action, e.g., if the joint action is flexion and the active muscles are agonists, then
the active muscle group is the flexor group (the active muscles are flexors).
b. If the active muscles are antagonists to the joint action - the muscles produce a torque in the opposite
direction of the joint action, e.g., if the joint action is flexion and the active muscles are antagonists,
then the active muscle group is the extensor group (the active muscles are extensors).
c. If the active muscles are stabilizers, then the active muscle group must be determined by an analysis
of what other torques act around the joint.
5. Identify the specific muscles in the muscle group. Use your knowledge of functional anatomy or look in
your anatomy textbook.
In lab activities:
Together, the class will analyze the following activities. For each phase of each activity and for each joint,
identify the joint action occurring, the type of muscular contraction, the role of the active muscles, and the
active muscle group. A sample analysis of a bench press is shown.
1. BENCH PRESS Phases: up and down Joints: elbow and shoulder
2. PUSH UP Phases: down and up Joints: elbow and shoulder
3. SIT UP Phases: up and down Joints: hip and intervertebral

5-6
Name ____________________________________________ page 2
EXAMPLE ANALYSIS OF BENCH PRESS (wide grip)
Phase of
Joint
Muscle
Joint
Motion
Action
Contraction
(not position)
Role of
Active
Muscles
Active
Muscle
Group
ELBOW DOWN flexion eccentric antagonist extensors*
SHOULDER
UP extension concentric agonist extensors
DOWN
horizontal
eccentric antagonist
horizontal
abduction
adductors**
horizontal
horizontal
UP
concentric agonist
adduction
adductors
*Active elbow muscle group and muscles: extensors: triceps, anconeus
**Active shoulder muscle group and muscles: horizontal adductors - pectoralis major, anterior deltoid,
coracobrachialis
1. SPRINTING: Analyze the sprinter (Coby Miller) shown in the sequence photos included with in Lab #2 by
completing the charts on pages 4 and 5. The analysis will encompass one full stride from Frame 1 through
Frame 8. Seven phases will be analyzed, each phase representing the movement occurring from one frame to
the next. Analyze the movements at the right hip, right knee, right ankle, right shoulder, and right elbow
joints.
The charts you complete on pages 2 through 4 are your write up for this lab. You are allowed (and encouraged)
to use a pencil when completing the charts for this lab write up.
SPRINTING
Joint
Frames
Joint
Action
(not position)
Muscle
Contraction
Role of
Active
Muscles
Active
Muscle
Group
RIGHT 1-2
HIP 2-3
3-4
4-5
5-6
6-7
7-8
RIGHT 1-2
KNEE 2-3
3-4
4-5

Name ____________________________________________ page 3
6-7
7-8
RIGHT 1-2
ANKLE 2-3
3-4
4-5
5-6
6-7
7-8
Identify each active hip muscle group and list the specific muscles within each group:
SPRINTING (continued)
Joint Frames
Joint
Action
(not position)
Muscle
Contraction
Role of
Active
Muscles
Active
Muscle
Group
RIGHT 1-2
SHOULDER 2-3
3-4
4-5
5-6
6-7
7-8
RIGHT 1-2
ELBOW 2-3
3-4
4-5
5-6
6-7
7-8

Name ____________________________________________ page 4
Identify each active ankle muscle group and list the specific muscles within each group:
Identify each active shoulder muscle group and list the specific muscles within each group:
Identify each active elbow muscle group and list the specific muscles within each group:

Name ____________________________________________
page
Summary of the analysis procedures:
Identify joint action.
Is the work done positive or negative?
There is no joint action.
Positive work Negative work Zero work
What would happen if the muscles
were relaxed (not contracting).
Concentric contraction
Eccentric contraction
No joint
action
occurs
Joint action
occurs
Agonist
Antagonist
Isometric
contraction
Stabilizer
Active muscle group
exerts torque in same
direction as joint
action, i.e., if joint
action is flexion then
active muscle group is
flexors
Active muscle group
exerts torque in
opposite direction as
joint action i.e., if
joint action is flexion
then active muscle
group is extensors
No muscle
activity
Active muscle group exerts torque in
opposite direction as imagined joint action
i.e., if imagined joint action is flexion then
active muscle group is extensors