Methods and apparatus for using nuclear magnetic resonance to evaluate the muscle efficiency and maximum power of a subject during locomotion

Apparatus for evaluating the muscular performance of a living animal during locomotion by the animal, comprising:

• (a) an NMR analytical device comprising:
• (i) a hollow electromagnet having a bore in which an axial magnetic field is developed upon energization of said electromagnetic, the bore being of sufficient size to receive said animal, (ii) means for locating said animal within said bore in such a location that during said locomotion a preselected locomotion producing muscle mass of the animal is located within a region of homogeneous axial magnetic field, (iii) means for interrogating with radio-frequency energy pulses predetermined atoms of the biochemicals within said muscle mass while the muscle mass is located within said region of homogeneous axial magnetic field, and (iv) means for developing, in response to said interrogation, signals representative of a measured biochemical relationship within said muscle mass at the time of interrogation,
• (b) means for causing locomotion of the animal while in said bore at varying rates of work that cause said biochemical relationship to vary within said muscle mass as a function of the level of exercise stress to which the animal is subjected,
• (c) means for measuring the rate of work performed by said animal while engaged in locomotion within said bore during a test of the animal,
• (d) means for relating the measured biochemical relationship in said muscle mass to the rates of work then being performed by said animal to provide an efficiency profile for said muscle mass, and
• (e) means for evaluating the ability of said muscle mass to recover from said exercise, comprising means for recording or observing the return toward a normal at-rest value of said biochemical relationship or a quantity based upon at least said biochemical relationship.

A method of evaluating the performance ability and ability to recover from exercise of horses comprising:

• (a) subjecting individual horses in a group of horses having similar genetic make-up to tests in which there is obtained for each of the individual horses an efficiency profile and ability to recover from exercise, the test for each horse comprising placing said horse in the bore of the electromagnet of an NMR analytical device, exercising the horse by utilizing a treadmill beneath the horse to produce locomotion of the horse at different rates of work while is said bore, measuring during said locomotion the rate of work performed by the horse and concurrently measuring with the NMR analytical device the following ratio of phosphorus-containing components within a locomotion producing muscle mass of the horse:
• Pi/PCr, where Pi is the concentration in said muscle mass of inorganic phosphate and PCr is the concentration in said muscle mass of phosphocreatine, the efficiency profile being a representation of work rate versus Pi/PCr for different levels of exercise stress, and determining said ability to recover by at least observing the return toward normal at-rest values of Pi/PCr or a quantity based upon Pi/PCr,
• (b) storing said efficiency profiles and abilities to recover in a data base,
• (c) developing an efficiency profile for another individual horse having a genetic make-up similar to those of the horses in said group, and evaluating the ability of said other horse to recover from strenuous exercise, by subjecting said other individual horse to the same test and measurements as defined in paragraph (a), and
• (d) comparing at least one of (i) the efficiency profile of said other horse with those stored in said data base and (ii) the ability to recover of said other horse with those abilities stored in the data base.

A method for evaluating the muscle efficiency and ability to recover from exercise of a subject during locomotion, comprising:

• (a) placing the subject within the bore of the electromagnet of an NMR analytical device,
• (b) exercising said subject by utilizing a treadmill beneath the subject to produce locomotion of the subject at different rates of work while in said bore and measuring with the NMR analytical device at different rates of work the following ratio of phosphorus-containing components within a locomotion-producing muscle mass of the subject:
• Pi/PCr
• where Pi is the concentration in said muscle mass of inorganic phosphate and PCr is the concentration in said muscle mass of phosphocreatine,
• (c) relating said values of Pi/PCr measured during locomotion to the rates of work then being performed by said subject to provide an efficiency profile for said muscle mass, and
• (d) recording or observing the return toward normal at-rest vales of at least one of Pi and PCr or a quantity based upon at least one of Pi and PCr.

A method of evaluating the maximum work rate Vm and ability to recover from exercise of a subject without dangerously stressing the subject comprising:

• (a) placing the subject on a treadmill located within the bore of an electromagnet of an NMR analytical device,
• (b) causing the subject to engage in locomotion on the treadmill, thereby causing the following biochemical relationship within a major muscle mass relied upon by the subject for locomotion to vary as a function of the subject's work rate V on the treadmill:
• Pi/PCr
• where Pi is the concentration in said muscle mass of inorganic phosphate, and PCr is the concentration in said muscle mass of phosphocreatine,
• (c) measuring with the NMR analytical device while the subject is engaging in locomotion on the treadmill:
• Pi/PCr for a work rate V that does not dangerously stress the subject,
• (d) determining the maximum work rate Vm from the following relationship:
• ##EQU5## where Km is Michaelis' affinity constant, and S is representative of Pi/PCr measured for said work rate V, and
• (d) recording or observing the return toward normal at-rest values of at least one of P and PCr or a quantity based upon at least one of Pi and PCr, whereby said ability to recover is indicated.

A method for evaluating the ability of a subject to recover from strenuous exercise, comprising:

• (a) subjecting the subject to strenuous exercise;
• (b) measuring, with an NMR device, at least one of the biochemical relationships present within a muscle mass of the subject following said strenuous exercise;
• and
• (c) recording or observing the return toward normal at-rest values of at least one of the measured relationships or at quantity based upon at least one of the measured relationships while the subject continues to exercise at a leisurely pace.

A method of evaluating the exercise performance ability and ability to recover from exercise of humans comprising:

• (a) subjecting individual humans in a group of humans having similar genetic make-up to tests in which there is obtained for each of the individual humans an efficiency profile and an indication of the human's ability to recover from exercise, the test for each human comprising placing said human in the bore of the electromagnet of an NMR analytical device, exercising the human by utilizing a treadmill beneath the human to produce locomotion of the human at different rates of work while in said bore, measuring during said locomotion the rate of work performed by the human and concurrently measuring with the NMR analytical device the following ratio of phosphorus-containing components within a locomotion-producing muscle mass of the human:
• Pi/PCr, where Pi is the concentration in said muscle mass of inorganic phosphate and PCr is the concentration in said muscle mass of phosphocreatine, the efficiency profile being a representation of work rate versus Pi/PCr for different levels of exercise stress, and recording or observing the return, toward normal at-rest values, of at least one of Pi and PCr or a quantity based upon at least one of Pi and PCr,
• (b) storing said efficiency profiles and indications of ability to recover in a data base,
• (c) developing an efficiency profile and information related to the ability to recover from exercise for another individual human having a genetic make-up similar to those of the humans in said group by subjecting said other individual human to the same test and measurements as defined in paragraph (a), and
• (d) comparing the efficiency profile and ability to recover from exercise of said other human with those stored in said data base.