I would guess that your vertical jump would suffer from the usual cycling training. Cycling is an endurance sport, emphasis on slow twitch muscles, vs. jumping, emphasis on fast twitch. The two types can convert back and forth to quite an extent with training. The same cyclist can train either to be a sprinter or a climber, and be fairly good at either one, but not as good at both at once. Of course if you never had a good jump, maybe it's genetics for you. Cycling won't help though.
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