1 The total training workload; training effort. According to the principle of progressive overload, in order to improve physical fitness, exercise must be intense enough to require more effort than normal. The method of determining that training intensity gives maximum benefits varies with each fitness component. Flexibility, for example, requires that muscles are stretched beyond their normal length; cardiovascular fitness requires elevating the heart rate above normal (see Karvonen method); and strength-training requires increasing resistance above normal loads (see repetition maximum). See also minute ventilation method.
2 In weight training, the actual resistance lifted expressed as a percentage of the maximum weight (1RM). Therefore, if the 1RM for a particular exercise is 120 kg then a weight of 60 kg would be a 50% intensity.