Pedal Stroke

Sorry no video… I was spinning the other day on the trainer and when I turned the TV off I noticed my pedal stroke head on. The left leg compared to the right appeared to extend out on the up stroke and then correct itself on the downstroke. Is the genetic, equipment relate or just bad mechanics?

Sorry no video… I was spinning the other day on the trainer and when I turned the TV off I noticed my pedal stroke head on. The left leg compared to the right appeared to extend out on the up stroke and then correct itself on the downstroke. Is the genetic, equipment relate or just bad mechanics?
Most likely bad mechanics but it could be something structural.