Jump
19th March 2008 - Squat Jumps with 183 kg, calculations show a 34 mm jump. Note the bar to the immediate left of my left hand travels roughly the bar's diameter (30 mm). The two frames show last contact with the ground and highest point of the jump on the second rep with 183 kg.
Jump Squats are, in some quarters, supposed to be 'very dangerous' - some would have you believe that they are on a par with jumping off a skyscraper and thus certain to induce a state of a messy death. Is this true? There's only one way to find out...
Actually Jumping
As predicted in Physics I was not damaged in any way by the Jump Squat.
But is jumping with such 'large' weights of any use? Who knows... I only did it because some fellow said it was impossible to do so with 400 lbs.
With 183 kg (403.4 lbs) I was predictably unable to jump very high, but I managed to clear the floor for a small hop.
Here are the details;
Wednesday 19 Mar 08 12:06 54MIN 79KG
LIFT WID
8' SQUAT JUMP 670
103 kg × 3 reps
123 kg × 2 reps
143 kg × 2 reps
163 kg × 2 reps
183 kg × 2 reps
SINGLE LATERAL
7 sets × 28½ kg × 10 reps per arm
>=60%
REP %MAX TON WORK IMP
151 82.5 5523.0 4817.8 14912.4
TN/RP 36.6
Video shows 143 kg and 183 kg;
I took the second jump of 183 kg and from the animation of the following two frames I calculated take-off velocity;
t = 0.133 seconds, s = 0.089 metres, g = 9.807 m.s-1
v = s/t = 0.089/0.133 = 0.670 m.s-1
Thus I calculated how high I jumped, the animation at the top of the page shows last contact with ground and highest point of jump;
s = v2/2g = 0.6702/2*9.807 = 0.034 metres = 34 mm
This is only an estimate because I'm calculating the velocity of the bar rather than my total centre of mass which would be slightly slower.
20th March 2008