Hadar indoor starting blocks are the best way to practice starts anywhere spiked starting blocks cannot be used. Will not harm gym floors, linoleum or concrete. An easy to use portable starting block for 800 and 400 runners looking for an advantage to a fast start, not suggested for competition sprint starts. Since there is no connection or adjustments to be made, a sprinter can try an infinite number of combinations to come up with an optimal start to transfer to competition starting blocks. Easy to rearrange starting block setups when practicing indoors. This is especially convenient for hurdlers whose steps might be more important than absolute acceleration out of the blocks.
The blocks are molded in our facility out of forgiving PVC high density plastic, giving them a weight and heft to stay put on the floor when placed. The smooth clean sticky bottom adheres well to almost all floors. Reverse the blocks and have a fellow runner or coach stand on the flap for added stability in start practices.