During competition preparation, a common practice of strength athletes is to utilize a short-term overload period followed by a taper to enhance strength performance. Three studies were conducted to evaluate changes in repetition velocity, estimated repetitions to failure (ERTF), and smartphone-derived heart rate variability (HRV) across overload and taper microcycles. The first study examined changes in bench press average concentric velocity (ACV) recorded during a load-velocity profile assessment consisting of loads ranging from 40-85% of one-repetition maximum (1RM). Additionally, this study investigated whether the load-velocity relationship could accurately predict bench press 1RM. Following an overload microcycle (PostOL), ACV of the load-velocity profile was significantly reduced compared to baseline (BL), however 1RM was unchanged. Following the taper (PostTP), ACV had returned to BL, while 1RM was significantly higher than PostOL and BL. The load-velocity profile was unable to accurately predict 1RM; however, the near perfect correlations suggest that it may be used to assess recovery and adaptation to resistance training. The second study evaluated the accuracy of ERTF during a bench press repetitions-to-failure assessment with 70% 1RM. There was no difference between ERTF and actual repetitions-to-failure (ARTF) during BL and PostOL; however, ARTF were significantly higher than ERTF at PostTP. Further, PostTP ARTF and ERTF were both significantly higher than PostOL, while ARTF were also higher than BL. Thus, the accuracy of ERTF is dependent on the proximity to muscular failure. The third study evaluated changes in HRV across overload and taper microcycles. Additionally, this study investigated the intra-day reliability of HRV measured upon waking (HRVM) and upon arriving to the training facility (HRVT). HRVM decreased significantly at PostOL, and returned back to baseline at PostTP. While HRVT followed a similar trend, there were no statistical difference across BL, PostOL, and PostTP. There were large to very large correlations between HRVM and HRVT during BL and PostOL, while the relationship at PostTP was not significant. Smartphone derived HRV, recorded upon waking, was sensitive to resistance training loads across an overload and taper microcycle in competitive strength athletes, whereas HRV taken just before the training session was not.