Staying strong and maintaining a leg-drive when in contact can help to gain territory, give teammates more time to support, and sometimes, counteract the tackle entirely.
In this clip, Eastbourne College score a try against Eton as a result of powerful running and leg-drive.
Staying strong in contact and using the leg-drive can commit extra defenders. If then, you can make an offload to supporting players, overlaps should be created. It is difficult to defend a strong offloading attack, and here, Stowe School are rewarded a try for their slick hands.
