know what really hurts....going by power levels (yes they are bullshit but its the only measurement we have) bardock in normal form is 10,000 in SSj he becomes 500,000....still under frieza's first form by 30k at least masked bardock can take on SSj4s T^T
juan zamorano Remember he was sucked into a i guess a time warp of some kind he may have not even been that hurt to begin with if he was a single zenkai boost wouldn't do much.
***** I doubt his training which is not very much on a planet with literally nothing to train with on it would gain him 3000 but if he did that would give him a power level of 950000 that's with the zenaki boost as i doubt he was able to train meaningfully his power level would be around 800000 its also possible he was not near death to begin with as he was transported into the past he could have taken some damage but not enough to be near death but i wouldn't know that, the best it would do would make him able to beat the first form (not the full power version that makes him slightly taller) but get crushed by the second form with no chance with third.
zenkai boosts depend on the damage taken, so Bardock would get a massive boost since he was about to die. Before you say he was not hurt because of the time warp, he got warped at the last second.