Arterial stiffness following heavy and moderate resistance training to volitional failure.

Arterial stiffness (AS) is an independent predictor of cardiovascular disease (CVD). The impact of RT on AS is not fully elucidated. Loading intensity (LI) is a well-researched training variable particularly in the field of muscular hypertrophy, yet there is a paucity of research directly examining the effects of different LIs on AS.Recent evidence suggests that LI is the key variable determining arterial responses to RT. It was observed that low to moderate LIs (< 70% 1RM) tend to decrease AS, whereas high LIs (> 70% 1RM) seem to increase AS. Nonetheless, the lack of control over proximity to failure in previous reports may be a confounding factor when interpreting these findings. Percentage-based load prescription (e.g., 10 repetitions at 75 %1RM) in previous studies may lead in ambiguity regarding how close to failure each participant approached. Evidence shows a great inter- individual variability in the number of repetitions performed in a given relative load, and proximity to failure is a main determinant of cardiovascular responses. Standardisation of effort allows for a more appropriate comparison of other training variables, such as load, since it ensures a more uniform stimulus among the conditions under investigation There is no study that has directly compared the effects of load on AS while standardising proximity to failure. Thus, the purpose of this study was to compare indices of AS between a strength-type RT scheme using heavier loads (4RM) and lower repetitions with a hypertrophy-type RT protocol using moderate loads and repetitions (12RM) while maintaining intensity of effort constant.