In football, as in most team sports, training is similar for all players, at least most of the time. Research has shown that during small-sided games players with high VO2max work at lower relative intensity compared with players with lower VO2max. This may cause two problems 1) some players train and thus improve more than others, and 2) some players may train very hard and if continue for weeks they can reach overreaching and overtraining.
Monitoring individual internal load, or the load imposed on the player´s body, by each training session is of high importance in modern football. One approach to do so is by multiplying the whole training rate of perceived exertion (RPE) by its duration. RPE should be recorded 30min after training using the category ratio scale (Borg scale) modified by Foster et al. (1995). Please note that rating should be based on the players feeling for the entire session.
Table. 0-10 Borg scale to use with football players (Impellizzeri et al., 2004).
Very, very easy
Impellizzeri et al. Med Sci Sports Exerc 36:1042-7, 2004