Apparatus is disclosed for monitoring strain and/or load applied to the bodyof a vertebral mammal. The apparatus includes means (10, 11) for measuringposition of the body relative to an inertial frame of reference and forproviding first data indicative of the position, wherein the means formeasuring position includes at least one inertial sensor such as anaccelerometer. The apparatus includes means (12, 15-19) for measuring muscleactivity and for providing second data indicative of the muscle activity. Theapparatus also includes means for storing the data and means for processingthe data to provide a measure of strain and/or load to the body. The strainand/or load is typically applied to the back of the mammal. A method ofmonitoring strain and/or load applied to the body of the vertebral mammal isalso disclosed.
