Most watches will have a 1sec recording rate.
So - it’s no good for Rapid Speed changes if you’re after speed
however, It will still measure that Guy A has gone 30m - it might just take an extra couple of seconds to really fine tune 30m v’s instantly. Overall - over say 5km of work on the field, if it’s only out 100m from the odd dodge and weave done faster than 1sec - It’s going to give you a far better idea on how far the guys do than Guessing.