The Single Leg Countermovement Jump isn't really a "single leg"...
Eamonn Flanagan@EamonnFlanagan
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May 10, 2026
~1 min read
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1
The Single Leg Countermovement Jump isn't really a "single leg" version of the CMJ
It has unique kinetic & kinematic characteristics. It offers a different strength quality challenge within it.
Its not a case of CMJ or SL-CMJ, but needing to understand what each test tells us
It has unique kinetic & kinematic characteristics. It offers a different strength quality challenge within it.
Its not a case of CMJ or SL-CMJ, but needing to understand what each test tells us
2
The SL-CMJ has greater "active limb load” vs CMJ. Approx. 1.6 times greater loading vs CMJ when normalised "per limb"
So the SL-CMJ is more "strength dominant" & concentric-biased. It likely uses the SSC to a lesser degree & involves slower rates of unloading & eccentric RFD
So the SL-CMJ is more "strength dominant" & concentric-biased. It likely uses the SSC to a lesser degree & involves slower rates of unloading & eccentric RFD
3
While contraction time ranges are similar, range of motion within this time is much ⬇️ than CMJ
The lower (per limb) force demands of CMJ mean greater ecc-velocities & greater ROM are used
In rehab settings, then this means greater challenge at knee through larger RoM
The lower (per limb) force demands of CMJ mean greater ecc-velocities & greater ROM are used
In rehab settings, then this means greater challenge at knee through larger RoM
4
CMJ trends to "Interlimb" compensatory expression. Athletes may shift load away from compromised limbs to the uninvolved side
The SL-CMJ tends to have a more "Interjoint" compensations.
A strong joint (hip/ankle) may mask a weak one (knee) within the compromised limb
The SL-CMJ tends to have a more "Interjoint" compensations.
A strong joint (hip/ankle) may mask a weak one (knee) within the compromised limb
5
Its not a case of "which test is better?"... both tests are useful.
CMJ is an all round tool - used often in training for long term development tracking & as a reference point early rehab settings
SL-CMJ can be used in more formal testing sessions & in mid- to late- stage rehab
CMJ is an all round tool - used often in training for long term development tracking & as a reference point early rehab settings
SL-CMJ can be used in more formal testing sessions & in mid- to late- stage rehab
6
@MattSinisc75247 So more "concentric biased actions" may involve:
Less eccentric unloading
Slower rates of ecc unloading
Slower ecc RFD
Less ecc impulse vs con impulse (vs CMJ)
Smaller ratio of P1:P2 concentric force production
"Peak force" more likely to occur after max CoM displacement
Less eccentric unloading
Slower rates of ecc unloading
Slower ecc RFD
Less ecc impulse vs con impulse (vs CMJ)
Smaller ratio of P1:P2 concentric force production
"Peak force" more likely to occur after max CoM displacement