Mining reactive triplet carbonyls in biological systems.

Aliphatic triplet carbonyls can be treated as short-lived radicals, since both species share similar reactions such as hydrogen atom abstraction, cyclization, addition, and isomerization. Importantly, enzyme-generated triplet carbonyls excite triplet molecular oxygen to the highly reactive, electrophilic singlet state by resonance energy transfer, which can react with proteins, lipids, and DNA. Carbonyl triplets, singlet oxygen, and radicals are endowed with the potential to trigger both normal and pathological responses. In this paper, we present a short review of easy, fast, and inexpensive preliminary tests for the detection of transient triplet carbonyls in chemical and biological systems. This paper covers direct and indirect methods to look for triplet carbonyls based on their spectral distribution of chemiluminescence, photoproduct analysis, quenching of light emission by conjugated dienes, and enhancement of light emission by the sensitizer 9,10-dibromoanthracence-2-sulfonate ion (DBAS).

Static Stretch Performed After Strength Training Session Induces Hypotensive Response in Trained Men.

Sousa, AC, Gomes, TM, Sousa, MS, Saraiva, AR, Araujo, GS, Figueiredo, T, and Novaes, JS. Static stretch performed after strength training session induces hypotensive response in trained men. J Strength Cond Res 33(11): 2981-2990, 2019-The purpose of this study was to compare the acute effect of 3 different combinations between passive static stretching exercises (SE) with resistance training (RT) on blood pressure (BP) response in normotensive trained men. Twenty-six volunteer subjects (age: 26.1 ± 5.4 years; body mass: 86.5 ± 10.5 kg; height: 1.78 ± 0.6 cm) participated in this study. After assessing 10 repetition maximum loads for the bench press, lat pulldown, shoulder press, leg press, leg extension, and leg curl, the subjects were randomly assigned on 3 experimental conditions: (a) static SE were performed before the RT session (SE + RT); (b) static SE were performed after the RT session (RT + SE); and (c) static SE were performed between the RT session (RTSE). The BP was measured for 60 minutes after the RT session. The 2-way analysis of variance for repeated measures showed no significant difference (p > 0.05) between the experimental conditions. In within comparisons, only the RT + SE experimental condition did not cause significant increases (p = 0.07) on systolic blood pressure (SBP) when compared the baseline and post-test moments (132.2 ± 10.7 vs. 141.3 ± 18.1 mm Hg). In addition, hypotensive effects were found in SBP only in the RT + SE experimental condition when compared SBP baseline (132.2 ± 10.7 mm Hg) vs. SBP30 minutes (121.7 ± 11.8 mm Hg; p = 0.04), SBP45 minutes (120.6 ± 9.8 mm Hg; p = 0.03), and SBP60 minutes (120.0 ± 7.9 mm Hg; p = 0.00). These findings suggest that performing static SE after the RT session provide an ideal combination for a postexercise hypotensive response from 30 minutes after exercise (and this change was enhanced up to 60 minutes). In conclusion, strength and conditioning professionals can prescribe static SE after RT if the goal is to reduce blood pressure after training.

Acute effects of different stretching techniques on the number of repetitions in a single lower body resistance training session.

This study aimed to investigate the acute effects of passive static and ballistic stretching on maximal repetition performance during a resistance training session (RTS). Nine male subjects underwent three experimental conditions: ballistic stretching (BS); passive static stretching (PSS); and a specific warm-up (SW). The RTS was composed of three sets of 12RM for the following exercises: leg press 45 (LP), leg extension (LE), leg curl (LC), and plantar flexors (PF). Performance of six sessions was assessed 48 hours apart. The first visit consisted of a familiarization session including stretching methods and exercises used in the RTS. On the second and third visit, a strength test and retest were performed. During the fourth to the sixth visit, the volunteers randomly performed the following protocols: BS+RTS; PSS+RTS; or SW+RTS. For the sum of the RM number of each three-set exercise, significant differences were found between PSS vs. SW for the LP (p = 0.001); LE (p = 0.005); MF (p = 0.001); and PF (p = 0.038). For the comparison between the methods of stretching PSS vs. BS, significant differences were found only for the FP (p = 0.019). When analyzing the method of stretching BS vs. SW, significant differences were found for the LP (p = 0.014) and MF (p = 0.002). For the total sum of the RM number of three sets of the four exercises that composed the RTS, significant differences were observed (p < 0.05) in the following comparisons: PPS vs. SW (p = 0.001), PPS vs. BS (p = 0.008), and BS vs. SW (p = 0.002). Accordingly, the methods of passive static and ballistic stretching should not be recommended before a RTS.

Acute effects of a warm-up including active, passive, and dynamic stretching on vertical jump performance.

The purpose of this study was to examine the acute effects of 3 different stretching methods combined with a warm-up protocol on vertical jump performance. Sixteen young tennis players (14.5 ± 2.8 years; 175 ± 5.6 cm; 64.0 ± 11.1 kg) were randomly assigned to 4 different experimental conditions on 4 successive days. Each session consisted of a general and specific warm-up, with 5 minutes of running followed by 10 jumps, accompanied by one of the subsequent conditions: (a) Control Condition (CC)-5 minutes of passive rest; (b) Passive Stretching Condition (PSC)-5 minutes of passive static stretching; (c) Active Stretching Condition (ASC)-5 minutes of active static stretching; and (d) Dynamic Stretching Condition (DC)-5 minutes of dynamic stretching. After each intervention, the subjects performed 3 squat jumps (SJs) and 3 countermovement jumps (CMJs), which were measured electronically. For the SJ, 1-way repeated measures analysis of variance (CC × PSC × ASC × DC) revealed significant decreases for ASC (28.7 ± 4.7 cm; p = 0.01) and PSC (28.7 ± 4.3 cm; p = 0.02) conditions when compared with CC (29.9 ± 5.0 cm). For CMJs, there were no significant decreases (p > 0.05) when all stretching conditions were compared with the CC. Significant increases in SJ performance were observed when comparing the DC (29.6 ± 4.9 cm; p = 0.02) with PSC (28.7 ± 4.3 cm). Significant increases in CMJ performance were observed when comparing the conditions ASC (34.0 ± 6.0 cm; p = 0.04) and DC (33.7 ± 5.5 cm; p = 0.03) with PSC (32.6 ± 5.5 cm). A dynamic stretching intervention appears to be more suitable for use as part of a warm-up in young athletes.

Acute effects of two different stretching methods on local muscular endurance performance.

The purpose of this study was to assess the acute effects of the static and proprioceptive neuromuscular facilitation (PNF) stretching methods on local muscular endurance performance at intensities between 40 and 80% of 1 repetition maximum (1RM) for the knee extension (KE) and bench press (BP) exercises. Fifteen male volunteers (23.9 ± 4.3 years; 174.5 ± 8.5 cm; and 77.8 ± 7.6 kg), who were nonathletes but had previous experience in resistance training, volunteered for this study. Participants were assigned to 9 randomly ordered experimental conditions, in which all subjects performed endurance tests at 40, 60, and 80% of 1RM, preceded by static stretching (SS), PNF, and no stretching (NS) in the KE and BP exercises. One-way repeated-measures analysis of variance (NS × SS × PNF) revealed an influence of stretching for all intensities only when the PNF treatment was used. Significant differences (p < 0.05) were found in the KE exercise, with reductions in the number of repetitions when comparing PNF40 (23.7 ± 2.7) to NS40 (27.5 ± 3.6); PNF60 (12.6 ± 2.8) to SS60 (16.5 ± 4.1) and NS60 (17.3 ± 3.2); and PNF80 (6.3 ± 1.7) to SS80 (9.9 ± 2.5) and NS80 (9.8 ± 2.3) conditions. Significant differences (p < 0.05) were also found for the BP exercise with decreases in the number of repetitions when comparing PNF60 (13.7 ± 2.8) to NS60 (17.0 ± 3.0) and PNF80 (6.2 ± 2.2) to NS80 (8.7 ± 2.3) conditions. These findings suggest that for the intensities studied (40, 60, and 80% 1RM), only the PNF method decreased muscle endurance. Strength and conditioning professionals may want to consider avoiding PNF stretching before activities requiring local muscular endurance performance.