What kind of exercises did you do and how long did you hold the contraction on average?
Exertions are approx 3-4 seconds followed by a quick flex/extension of a second or three, run to 10 repeats.
Upper body:
Stand with trunk about a foot away from doorframe. Lower hand pulls at about hip level, upper hand pushes about collarbone level.
Using anterior chain plus push with legs, plus push/pull upper body, attempt to fold the doorframe at the lower pulling hand, pushing the upper part away from you, pulling lower part toward. Use arm circles or quick horizontal swing of the arm fore and aft between exertions.
Shift push/pull assignments for hands so now you are attempting to fold the upper half toward you, and lower half away, using posterior chain to brace/power the action.
For legs, get a step back from the doorframe, bring up lead leg and brace ball of foot against frame, both legs bent about 30 degrees. Attempt to drive the lead leg up and into the frame at about 45degrees. You will feel this more in the glutes/hamstrings of the support leg.
Face away from the frame and lean forward about 45degrees, brace trailing foot, flat to the doorframe behind you. Again, both legs bent about 30 degrees at the knee. Attempt to drive trailing foot back and up into the frame. This time you should feel it more in quads of bracing leg.
Both leg movements you should feel strong adductor activation. Execute a quick extension/flexion of both legs after each exertion.
All of these are unilateral. I have some others that use only doorframe, basement post, small tree etc but these are the initial batch.