1. A garment to be positioned about one or more body portions of a person performing a physical activity, the garment comprising: a training region intended to be in substantially constant physical contact with the one or more body portions of the person performing a physical activity and having a training region elasticity; a garment region having a garment region elasticity, the garment region stretching a greater distance as the result of an applied force than the training region under the same applied force; and the training region at least partially defining a tensioning system of a biofeedback device, the biofeedback device being configured to provide feedback forces having a magnitude and a direction to the person performing a physical activity when the person performing a physical activity's biomechanic position is sub-optimal, the feedback forces indicating to the person performing a physical activity that their biomechanic position is sub-optimal and indicating to the person performing a physical activity how to adjust their one or more body portions towards a more optimal biomechanic position; wherein the biofeedback device is configured to sense and correct sub-optimal biomechanic positions, the sub-optimal biomechanic positions including static postures and dynamic postures; wherein when the person's biomechanic position is substantially optimal, the person performing a physical activity receives substantially no feedback forces indicating to the person performing a physical activity that their biomechanic position is sub-optimal; wherein the magnitudes of the feedback forces generally increase the farther the person performing a physical activity is from an optimal biomechanic position.