Hi Simon, sets, reps and loading are very complex issue, and you may find what works for someone else does not work for you, it is really a try it and see situation but to give you a starting point, when you are racing, I would focus on 2 workouts a week leading into a weekend race, and would work heavier on the monday or tuesday, around 70 – 80% of maximum load and perform 6 sets x 3 reps with attempted acceleration, a controlled lowering and then attempting to lift the weight as fast as possible even if it does not appear to move quickly the attempt will preferentially recruit the fast twitch fibers, then on the thursday I would work the opposite end of the spectrum and perform 3 sets x 6 reps with a load between 25 – 40%, moving the bar very quickly, in the off season I would be looking at loads cycled over a 3 week period attempting to get as strong as you can, reps less than 6 for 3 – 6 sets, concentrating on compound movements.
We have had a lot of success by contrasting our weight room work with our speed work on the field as per below:
F1. Dynamic Movement Warm up
Micro Fastfoot Ladders and Quicken Micro and Mini hurdle sequences
F2. Medicine Ball throws and acceleration sprints over 10 – 15 metres
G1. Depth or Box Jumps in gym
F3. Assisted sprints utilizing short (mini slingshot overspeed trainers)and/or long (slingshot overspeed trainers)
G2. Power Snatch from blocks set at knee height, Block Cleans or Jump Squats (3 sets of 6 reps at 30 – 40%)
F4. Maximal velocity work over 30 – 60 metres
G3. Clean or Snatch Pulls from the floor or Band Box Squats (6 sets of 3 reps at 60 – 80%)
F5. Resisted speed efforts utilizing either pro power speed resistors, power speed chutes, power speed sleds, these are often performed with a contrast sprint after the loaded sprint
G4. Trap Bar Dead lifts or Front or Back Squats (6sets of 3 reps at > 90% 1RM loading)
The F refers to field and the G to the gym, possibly you could do something similar in your sport of BMX, by practicing the start and exploding out of the blocks for say 15 seconds and then doing a weight room exercise or something similar, another method in the gym when working with a partner would be the “I go you Go” method which you can read on this web site or the full body circuit as outlined below:
Full Body Power Circuit (5 sets x 3 – 5 reps – @60 – 80%)
Warm up with KB swings and skipping
1/4 Explosive Squat or Jump Squat or Band Box Squat or BW Jumps
Clean Push Press from Blocks or Snatch from Blocks
Jammer or Push Press or Band Bench Press
Dominator or Hammer Push/Pull
5 times through 3 – 5 reps per exercise
Best wishes, ashley