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1. CONCENTRIC- active shortening vs ECCENTRIC- active lengthening
Example. Biceps curl, when moving towards elbow flexion, biceps contracts concentrically, when lowering it towards extension, biceps contracts eccentrically.
2. CONCENTRIC is working against gravity usually opposite the direction of gravity while ECCENTRIC is also working against gravity however in the direction of gravity.
Example. Squatting, when the knee starts bending, gravity is pulling down more the body, so the QUADRICEPS contracts eccentrically to allow a controlled fashion.
However when rising from a full squat position, the Quads need to contract concentrically to straighten the knee while counteracting the gravity. Same through when ascending the stairs, quads contract concentrically and contracts eccentrically when descending the stairs.
Note. In concentric contraction, force generated by mm is always less than the muscle’s maximum force.
In eccentric contraction, external force in the muscle is always greater than the actual force a muscle can generate. External force can be a form of gravity, inertia or opposing muscle forces.
Now, here is the table that I am referring to. E stands for Eccentric, C for Concentric, N is for no contraction. We will start with STANCE PHASE.
HS
FF
MS
HO
TO
HIP
E
C
C/N
E
C
KNEE
C
E
C/N
N
E
ANKLE
E
E
E
E
C
Y123345t5566y77777777777
TIP: try to memorize every letters, because it will help you answer complex questions in NPTE regarding gait. I suggest memorizing it horizontally, as if singing them like, e, c, cn, e ,c..So that’s for hip, now go to knee, you end with C in hip, this time you’ ll start with same letter C, now that will make it easier for you to memorize it.. Again same with ankle end with E at knee, now start on same letter E on ankle. Its easier in ankle coz all are Easy except for the last one that is C.
Now for the muscles involved, we will fill up again the table.
HS
FF
MS
HO
TO
HIP
G max
G max
G max
iliopsoas
iliopsoas
KNEE
quads
quads
quads
none
quads
ANKLE
TA
TA
CALF
CALF
CALF
Lastly, we will need the ROM that occurs in hip, knee and ankle joint in stance phase.
HS
FF
MS
HO
TO
HIP
20-30 F
5 E
0
10-20 E
0
KNEE
Full Ext
5-15 F
Slight E
0
30 F
ANKLE
0
10 PF
5-10 DF
10DF
20 PF
Tip: in order not to forget or not to get confused on these values, or in case you forget one of these, doing the actions will help you to get the normal range. You can also used your knowledge on the type of contractions, eccentric or concentric, in order for you to know what muscle is involve or what motion is needed.
Here is the narrative explanation of the above given table. On the stance phase of the HIP
HS- there is 20 to 30 deg of hip flexion and eccentric contraction of GMAX
FF- there is 5 deg of EXT (or moving into extension) with concentric contraction of G MAX
MS- hip is in neutral position; there is no activity or a little contraction of G MAX
HO- there is 10-20 degree of hip extension, and eccentric contraction of iliopsoas muscle (to resist too much or momentarily of flexion)
TO- there is 10- 0 deg of ext (going to neutral) and concentric contraction of iliopsoas
KNEE
Hs- There is full extension, concentric contraction of Quads
FF- knee is in 5-15 deg of flexion but this is an eccentric contraction of QUADS, to prevent buckling of the knee.
MS- knee is slightly extended, quads contracts concentrically on early stage to NO CONTRACTION at all.
HO- this is a bonus. No muscle activity here. (Red Sullivan)
TO- 0-30 deg of knee flexion, with eccentric contraction of quads.
ANKLE
HS- the ankle is at 90 deg or at 0 deg, pre tibials like TA acts eccentrically to prevent foot drop.
FF- from neutral, ankle goes to 10 deg of PF, with eccentric contraction of pre tibials
MS- from DF position on foot flat, ankle will move to 5 to 10 deg of DF, but this time ECCENTRIC contraction of calf muscle to prevent too much DF of tibia and fibula on fixed foot.
HO- there will still be 10 deg of DF by continues action of calf muscles.
TO- calf muscle will contract concentrically by 20 deg PF in preparation of swing phase.
FOR SWING PHASE IT WILL BE A LOT EASIER.
ACC- MS
MS - DEC
HIP
C
ILIOP
20-30 F
E
G-MAX
20-30 F
KNEE
C
Biceps femoris,grcilis,sartorius
30-60F
E
HAMS and concentric q’ceps
60F- 0
ANKLE
C
TA
20 DF
ISOMS
TA
NEUTRAL
HIP
ACC- MS – iliopsoas works concentrically flexing the hip to 20-30 deg
MS- DEC – there is continued hip flexion however, since its decelerating, eccentric is the type of contraction done by G MAX (to slow down the hip flexion)
KNEE
ACC- MS- there is 30-60 deg of knee flexion with eccentric contraction of HAMS
MS- DEC- again during MS to DEC, owing to slowing of movement, there should be eccentric contraction in straightening the knee in preparation of HS, so HAMS is responsible for 60 deg of knee flexion going to full extension.
ANKLE
ACC- MS – there is 20 deg of DF by concentric contraction of pre tibial muscles.
MS – DEC- pre tibials on this stage contracts ISOMETRICALLY.
Example. Biceps curl, when moving towards elbow flexion, biceps contracts concentrically, when lowering it towards extension, biceps contracts eccentrically.
2. CONCENTRIC is working against gravity usually opposite the direction of gravity while ECCENTRIC is also working against gravity however in the direction of gravity.
Example. Squatting, when the knee starts bending, gravity is pulling down more the body, so the QUADRICEPS contracts eccentrically to allow a controlled fashion.
However when rising from a full squat position, the Quads need to contract concentrically to straighten the knee while counteracting the gravity. Same through when ascending the stairs, quads contract concentrically and contracts eccentrically when descending the stairs.
Note. In concentric contraction, force generated by mm is always less than the muscle’s maximum force.
In eccentric contraction, external force in the muscle is always greater than the actual force a muscle can generate. External force can be a form of gravity, inertia or opposing muscle forces.
Now, here is the table that I am referring to. E stands for Eccentric, C for Concentric, N is for no contraction. We will start with STANCE PHASE.
HS
FF
MS
HO
TO
HIP
E
C
C/N
E
C
KNEE
C
E
C/N
N
E
ANKLE
E
E
E
E
C
Y123345t5566y77777777777
TIP: try to memorize every letters, because it will help you answer complex questions in NPTE regarding gait. I suggest memorizing it horizontally, as if singing them like, e, c, cn, e ,c..So that’s for hip, now go to knee, you end with C in hip, this time you’ ll start with same letter C, now that will make it easier for you to memorize it.. Again same with ankle end with E at knee, now start on same letter E on ankle. Its easier in ankle coz all are Easy except for the last one that is C.
Now for the muscles involved, we will fill up again the table.
HS
FF
MS
HO
TO
HIP
G max
G max
G max
iliopsoas
iliopsoas
KNEE
quads
quads
quads
none
quads
ANKLE
TA
TA
CALF
CALF
CALF
Lastly, we will need the ROM that occurs in hip, knee and ankle joint in stance phase.
HS
FF
MS
HO
TO
HIP
20-30 F
5 E
0
10-20 E
0
KNEE
Full Ext
5-15 F
Slight E
0
30 F
ANKLE
0
10 PF
5-10 DF
10DF
20 PF
Tip: in order not to forget or not to get confused on these values, or in case you forget one of these, doing the actions will help you to get the normal range. You can also used your knowledge on the type of contractions, eccentric or concentric, in order for you to know what muscle is involve or what motion is needed.
Here is the narrative explanation of the above given table. On the stance phase of the HIP
HS- there is 20 to 30 deg of hip flexion and eccentric contraction of GMAX
FF- there is 5 deg of EXT (or moving into extension) with concentric contraction of G MAX
MS- hip is in neutral position; there is no activity or a little contraction of G MAX
HO- there is 10-20 degree of hip extension, and eccentric contraction of iliopsoas muscle (to resist too much or momentarily of flexion)
TO- there is 10- 0 deg of ext (going to neutral) and concentric contraction of iliopsoas
KNEE
Hs- There is full extension, concentric contraction of Quads
FF- knee is in 5-15 deg of flexion but this is an eccentric contraction of QUADS, to prevent buckling of the knee.
MS- knee is slightly extended, quads contracts concentrically on early stage to NO CONTRACTION at all.
HO- this is a bonus. No muscle activity here. (Red Sullivan)
TO- 0-30 deg of knee flexion, with eccentric contraction of quads.
ANKLE
HS- the ankle is at 90 deg or at 0 deg, pre tibials like TA acts eccentrically to prevent foot drop.
FF- from neutral, ankle goes to 10 deg of PF, with eccentric contraction of pre tibials
MS- from DF position on foot flat, ankle will move to 5 to 10 deg of DF, but this time ECCENTRIC contraction of calf muscle to prevent too much DF of tibia and fibula on fixed foot.
HO- there will still be 10 deg of DF by continues action of calf muscles.
TO- calf muscle will contract concentrically by 20 deg PF in preparation of swing phase.
FOR SWING PHASE IT WILL BE A LOT EASIER.
ACC- MS
MS - DEC
HIP
C
ILIOP
20-30 F
E
G-MAX
20-30 F
KNEE
C
Biceps femoris,grcilis,sartorius
30-60F
E
HAMS and concentric q’ceps
60F- 0
ANKLE
C
TA
20 DF
ISOMS
TA
NEUTRAL
HIP
ACC- MS – iliopsoas works concentrically flexing the hip to 20-30 deg
MS- DEC – there is continued hip flexion however, since its decelerating, eccentric is the type of contraction done by G MAX (to slow down the hip flexion)
KNEE
ACC- MS- there is 30-60 deg of knee flexion with eccentric contraction of HAMS
MS- DEC- again during MS to DEC, owing to slowing of movement, there should be eccentric contraction in straightening the knee in preparation of HS, so HAMS is responsible for 60 deg of knee flexion going to full extension.
ANKLE
ACC- MS – there is 20 deg of DF by concentric contraction of pre tibial muscles.
MS – DEC- pre tibials on this stage contracts ISOMETRICALLY.
