Brief background: I am an experienced athlete, 30 yrs old, 190lb/5'11; I play soccer and have always had a very fast 300m.
Last couple of months, I have been doing crossfit. I have been going up in weights well, and am getting good progression in the olympic lifts (about +45 lbs every 2 months--I understand this will plateau, but it has been going well so far).
Since I was doing well, I decided to watch you tube videos on tips for olympic lifts. These involved adjustments to foot, ankle, and knee positioning to better activate the posterior chain.
I put these adjustments to the test about 2 weeks ago during a deadlift->front squat->burpee progression. I got an amazing workout and was sore for days--as if it was the first time I had ever squatted before.
However, about 4 days later, we did another leg intensive workout...and within minutes, I was nearly unable to stand, my cramping was so bad in the posterior pelvic crest area (right where the elastic band of the shorts sits along the lower back).
I figured this was due to new recruitment and soreness.
That being said, today we did a conditioning workout that involved 400m runs. During the first warm up run, I was cramping within 100m.
This continued and worsened throughout the workout (which involved dumbell thrusters and 400m runs.
Only 3 weeks ago, I was crushing 400m runs in ~1:15, even when alternating with weight workouts. Now--after just doing these exercises differently--I am cramping and can barely complete any workout involving the lower body.
I am trying to figure out how to fix this, since it is very alarming to go from a high level of performance to what feels like below-baseline level performance in just two weeks.
If it is a blood flow problem, ok I can buy lighter shorts; if it is a new muscle recruitment-pattern problem, ok, it'll go away when the muscles get stronger; but if it is some other kind of problem?
Is it abnormal?