The perfection of the capacity of the body to hold and express the higher forces has beneficial results for each level of the being. The physical body itself gains levels of energy and strength that cannot be achieved solely through usual physical culture and training. But it also acts as a more solid and responsive foundation for the action of the vital, emotional mental, and spiritual powers to act with a more intense and effective force than is usually possible.
Sri Aurobindo observes: The spiritual force will be able to do what it wills and as it wills in and through the body. It will be able to conduct an unlimited action of the mind or, at a higher stage, of the supermind without the body betraying the action by fatigue, incapacity, inaptitude or falsification. It will be able too to pour a full tide of the life-force into the body and conduct a large action and joy of the perfected vital being without that quarrel and disparity which is the relation of the normal life-instincts and life-impulses to the insufficient physical instrument they are obliged to use. And it will also be able to conduct a full action of the spiritualised psychic being not falsified, degraded or in any way marred by the lower instincts of the body and to use physical action and expression as a free notation of the higher psychical life. And in the body itself there will be a presence of a greatness of sustaining force, an abounding strength, energy and puissance of outgoing and managing force, a lightness, swiftness and adaptability of the nervous and physical being, a holding and responsive power in the whole physical machine and its driving springs of which it is now even at its strongest and best incapable.”
Sri Aurobindo, The Synthesis of Yoga, Part Four: The Yoga of Self-Perfection, Chapter 14, The Power of the Instruments, pp. 703-704