Does weekly internal training load vary in professional soccer players?

Quantification of training load in professional soccer players have produced similar findings where team mean to weekly training load (w-TL) barely varies throughout the season. The aims of the present study were (a) to analyze respiratory and muscular weekly perceived exertion, and (b) to determine the variability during pre-season and in-season competitive period taking into account each player individually. Twenty-one professional soccer players belonging a 2nd Division soccer team participated in this study. Differentiated w-TL accumulated was quantified during 44-week of pre-season and season period (i.e., 6-week of pre-season and 38-week of season). The perceived level of exertion for leg local-muscular in weekly training load (w-TLmus) was higher (P < 0.05) than perceived exertion for central-respiratory in weekly training load (w-TLres) both for pre-competition and for competition period. Moreover, larger w-TL during pre-competitive period than competitive period in w-TLres and w-TLmus were shown. The intra-player variability showed higher values during pre-competition period (CV: from 30.4 to 75.4% and from 15.3 to 76.9%) than competitive period (CV: from 21.2 to 46.1% and from 22.1 to 44.2%) in both w-TLres and w-TLmus, respectively. The current study suggest that soccer players manage loads in a different way during pre-season and in-season periods.