Analysis is fine.
Tis a training method developed by Guy, through of which the trainee straps on a pair of weights on their legs with the use of some fuuinjutsu. The trainee must then grow accustomed to the extra weight on their legs, till they can move and fight without feeling burdened. As they grow more comfortable with the weights, they can add even more weight to advance the training. Eventually at a certain level once the trainee completely adapts to the weights, capable of fighting and moving as they normally would, they can then take off the weights making their body feel extremely lighten. The strength of their legs also drastically increases, as such they are able to run extremely fast speeds and have heightened power behind their kicks.