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Capsaicinoids and their analogs (CAP) are found in various types of peppers and have received great attention as weight management agents. An increase in energy expenditure and fat oxidation at rest, along with appetite and energy intake reduction has been reported. CAP supplementation has also been indicated to increase exercise performance. Another potential effect of CAP during exercise is to increase energy expenditure and fat oxidation. Thus, the present systematic review aimed to compare the energy expenditure (EE) and substrate oxidation during exercise with CAP administration, or placebo (no CAP administration), in acute studies. Ten studies met our inclusion criteria for EE, including one with mice. Only one study reported higher EE during exercise compared to non-CAP conditions. We found seven studies that met our inclusion criteria for substrate oxidation measurement during exercise. One study reported lower fat oxidation during CAP conditions, while two reported higher fat oxidation with CAP supplementation. From studies retrieved, some reported increased EE and fat oxidation at rest, which means that the effect of CAP at rest was not carried over into exercise. In conclusion, CAP seems not to be a potential ergogenic aid to affect EE considering the studies retrieved in this current review; however, inconsistent results have been reported regarding to substrate oxidation. Further research should clarify the effect of CAP on substrate oxidation during exercise.

PRUPOSE: To investigate the effects of a 5-km high-intensity interval exercise (HIIE) on heart rate variability (HRV) and subsequent strength performance. METHODS: nine trained males performed a control session composed of a half-squat strength exercise (4 x 80% of one repetition maximum – 1RM) in isolation and 30-min, 1-, 4-, 8- and 24-h after an HIIE (1-min at the velocity peak:1-min passive recovery). All experimental sessions were performed on different days. The maximum number of repetitions and total weight lifted during the strength exercise were registered in all conditions; in addition, prior to each session, HRV were assessed [beat-to-beat intervals (RR) and log-transformed of root means square of successive differences in the normal-to-normal intervals (lnRMSSD)]. RESULTS: Performance in the strength exercise dropped at 30-min (31%) and 1-h (19%) post-HIIE concomitantly with lower values of RR (781±79 ms; 799±134 ms, respectively) in the same recovery intervals compared to the control (1015±197 ms). Inferential analysis did not detect any effect of condition on lnRMSSD, however, values were lower after 30-min (3.5±0.4 ms) and 1-h (3.3±0.5 ms) with moderate and large effect sizes (0.9 and 1.2, respectively) compared with the control condition (3.9±0.4 ms). CONCLUSION: Both RR and lnRMSSD seem to be associated with deleterious effects on strength performance, although further studies should be conducted to clarify this association.

The objective of the present study was to determine equations that could be used to estimate the load corresponding to the one-repetition maximum (1RM) based on the maximum number of repetitions (MNR) using submaximal loads in bench press, lat machine pull-down and leg curl exercises in strength-trained women (n = 20; 22 ± 3 years; 61 ± 7 kg; 165 ± 4 cm). The first test was the 1RM test. Next, the subjects performed the MNR test at intensities of 70, 80 and 90% of 1RM for all exercises on different days. A multiple linear regression model was used for the determination of each equation. Two criteria were applied to accept the equation: adjusted R² value (adj.R² > 0.80) and percent error (PE < 10%). For all exercises, the equations met the two criteria: bench press: adjR² = 0.89; PE = 5%; lat machine pull-down: adjR² = 0.84; PE = 5%; leg curl: adjR² = 0.82; PE = 7%. The application of the equations developed will require the selection of a random load and the number of repetitions performed at the same load to identify 1RM. It is recommended that the number of repetitions be within the range observed in this study: bench press (1-21), lat machine pull-down (2-20), and leg curl (1-14).

The objective of the present study was to determine equations that could be used to estimate the load corresponding to the one-repetition maximum (1RM) based on the maximum number of repetitions (MNR) using submaximal loads in bench press, lat machine pull-down and leg curl exercises in strength-trained women (n = 20; 22 ± 3 years; 61 ± 7 kg; 165 ± 4 cm). The first test was the 1RM test. Next, the subjects performed the MNR test at intensities of 70, 80 and 90% of 1RM for all exercises on different days. A multiple linear regression model was used for the determination of each equation. Two criteria were applied to accept the equation: adjusted R² value (adj.R² > 0.80) and percent error (PE < 10%). For all exercises, the equations met the two criteria: bench press: adjR² = 0.89; PE = 5%; lat machine pull-down: adjR² = 0.84; PE = 5%; leg curl: adjR² = 0.82; PE = 7%. The application of the equations developed will require the selection of a random load and the number of repetitions performed at the same load to identify 1RM. It is recommended that the number of repetitions be within the range observed in this study: bench press (1-21), lat machine pull-down (2-20), and leg curl (1-14).

This study aimed to analyze the effect of the time interval after high-intensity aerobic exercise on strength performance in individuals with different training backgrounds. Participants (n = 27) were divided into three groups according to their training backgrounds (aerobic, strength or concurrent) and submitted to eight sessions: (1) determination of the peak velocity (Vpeak) during the incremental treadmill test to exhaustion and familiarization of the evaluation of maximum strength (1RM) for the half-squat; (2) 1RM determination; and (3-8) randomly assigned experimental sessions consisting of either a strength exercise (SE), four sets at 80% of the 1RM, in which maximum number of repetitions (MNR) and the total volume performed (TV) was computed, and five sessions consisting of high-intensity intermittent aerobic exercise (100% of Vpeak - 1 min:1 min) totaling 5 km, followed by a SE with varying recovery intervals between activities (30, 60 minutes, 4, 8, and 24 hours). Comparisons for MNR and TV were made using two-way variance analysis (group and time interval) with repeated measures in the second factor. When significant differences were detected (P < 0.05), a Bonferroni and Dunnet post-hoc test were used. There was an effect of group for MNR, with the Aerobic Group performing a higher MNR compared to Strength Group (P = 0.002). Moreover, there was an effect of the time interval for MNR and TV, with reduction after 30 (P < 0.001 for both variables) and 60 minutes intervals (P = 0.035; P = 0.007, respectively) compared to the control condition. Thus, it is concluded that the drop in performance related to the SE activity occurred with the same magnitude and time interval for each of the groups.