Thank you for the above video-clip.
Remarkable. This is a form of Tong Bei Quan (through back boxing) - exactly the same principle that underlines our Longfist! There are many versions as this style is diverse. When the Hakka migrated they brought it Southward. It's not exactly the same - but close enough. Tong Bei is both a style and principle - akin to "putting your back into it" in the West"! In fact, the qi energy must flow up the spine and down the front unban unbroken cycle - expanding through mind awareness (intention) - into the entire body head to foot. This coincides with an aligned bone structure so that the bodyweight drops down through the centre of the bones into the ground. This is rooting. The bodyweight then rebounds back up through the centre of the bones and is omitted as concentrated force. All this is coordinated with deep and full breathing through the nose, mouth, both, or just one. Bodyweight power replaces muscular contraction power and I believe that there is a connection with the Taiji concept. As the spirit of our family version is the bear - we train to become stocky and rotund so that when we stand up - we appear big and intimidating - like a bear stood on its back legs. The thick muscle acts like a rubber tyre - so that strong external blows bounce off without damaging the inner organs. As this training involves running with heavyweights - the bones also harden - completing the two parts of the Iron Vest training. This process is helped by various parts of bone and limb striking, etc. If the bones are broken - the matter at hand is dealt with first before medical treatment is sought. Full weight both suddenly projected - and immediately withdrawn depending on circumstance.