In hand exercises are fantastic at building your horse’s strength without him having to balance himself and you. Working your horse in hand can give him a real confidence boost, as well as improving your trust and partnership, so they don't have to only be used if your horse is in rehab.
This exercise improves your horse’s overall flexibility and strengthens his stifle, it also works on strengthening the ligaments in his legs which are susceptible to injury.
The key to this exercise is to encourage your horse to do it slowly as this will build the strength in his stifle, which is key for impulsion from the hindquarters. Make sure you’re using a soft object in case your horse does stand on it, you don’t want him to become startled. You could use a pole on the ground to build your horse's confidence before introducing a hay bale, however only using a pole will not have the same strengthening effect as the bale as the horse will not need to lift as high and stretch as far.