Exercise alters the circadian rhythm of REV-ERB-α and downregulates autophagy-related genes in peripheral and central tissues.

The transcriptional repressor REV-ERB-α, encoded by Nuclear Receptor Subfamily 1 Group D Member 1 (Nr1d1), has been considered to play an essential role in the skeletal muscle oxidative capacity adaptation and muscle mass control. Also, this molecule regulates autophagy via the repression of autophagy-related genes both in skeletal muscle and brain regions. Classically, training programs based on endurance or strength characteristics enhance skeletal muscle mass content and/or oxidative capacity, leading to autophagy activation in several tissues. Thus, it seems that REV-ERB-α regulates similar responses induced by exercise. However, how this molecule responds to different exercise models/intensities in different tissues is still unclear. Therefore, the main aim was to characterize the responses of REV-ERB-α and autophagy-related genes to different exercise protocols (endurance/interval run/strength) in distinct tissues (gastrocnemius, soleus and hippocampus). Since REV-ERB-α presents a circadian rhythm, the analyses were performed in a time-course manner. The endurance and strength groups attenuated REV-ERB-α transcriptional response during the time course in gastrocnemius and soleus. Conversely, the interval group enhanced the Nr1d1 expression in the hippocampus. All protocols downregulated the REV-ERB-α protein levels in gastrocnemius following the exercise session with concomitant nuclear exclusion. The major autophagy-related genes presented downregulation after the exercise session in all analyzed tissues. Altogether, these results highlight that REV-ERB-α is extremely sensitive to physical exercise stimuli, including different models and intensities in skeletal muscle and the hippocampus.

Fatigue modifies hip and knee kinematics during single- and double-leg dynamic tasks: An investigation with female handball players.

This study investigated the effect of a handball-specific fatigue protocol on hip and knee kinematics. Twenty female handball athletes performed three trials of the single-leg landing (SLL), sidestep cutting manoeuvre (SCM), and drop vertical jump (DVJ) before and after the fatigue protocol. Knee and hip angle waveforms were compared using statistical parametric mapping (p < 0.05). During the SLL, the fatigue increased hip adduction (4-7% cycle) and knee abduction (4-9% and 25-27%). For the SCM, hip flexion was reduced under fatigue during 14-29% and 44-68% of the cycle. Similarly, the knee flexion decreased between 7-36% and 53-73%. Besides, during the fatigue state, the athletes reduced the hip abduction between 0-11% of the cycle and increased the knee abduction between 20-23%. During the DVJ task, when fatigued, the hip flexion decreased between 19-44% of the cycle and the knee flexion between 1-16% and 18-77%. The fatigue protocol altered the lower limb kinematics, decreasing knee and hip flexions during the SCM and DVJ and increasing the knee valgus during both single-leg landing tasks.

The Pre-Exhaustion Method Does Not Increase Muscle Activity in Target Muscle During Strength Training in Untrained Individuals.

This study investigated the effects of the pre-exhaustion method on electromyographic activity (root mean square and median frequency) at different interval sets. Twenty adults with little or no experience in strength training performed the seated row exercise until muscular failure, with or without completing a previous pre-exhaustion set in a pullover exercise. Surface electrodes were placed over the latissimus dorsi, teres major, biceps brachii, and posterior deltoid muscles of the dominant side. The results showed no effect of pre-exhaustion on EMG activity of latissimus dorsi target muscle for any interval sets. Regarding median frequency, our results showed a consistent decrease throughout the sets (p>0.05). Also, our results revealed a decrease in posterior deltoid median frequency with pre-exhaustion (p=0.001). We conclude that the pre-exhaustion method seems ineffective in increasing the EMG activity of the desired muscle throughout all repetitions of strength training. Furthermore, pre-exhaustion seems to be a good way to increase fatigue in the posterior deltoid muscle.

Applying Different Strategies of Task Constraint Manipulation in Small-Sided and Conditioned Games: How Do They Impact Physical and Tactical Demands?

This study aimed to investigate how different strategies of task constraint manipulation impact physical and tactical demands in small-sided and conditioned games (SSCG). Ten recreational U-17 soccer players participated in this study (16.89 ± 0.11 years). We used different strategies of task manipulation to design two 4 vs. 4 SSCG: Structural SSCG and Functional SSCG. In Structural SSCG, pitch format and goal sizes were manipulated, while in Functional SSCG, players were allowed to kick the ball twice and at least 5 passes to shoot at the opponent's goal. Players participated in four Structural and Functional SSCG, of five minutes duration with a two-minute interval in between. Players' physical performance and tactical behavior were assessed using the WIMU PROTM inertial device. Structural SSCG stimulated players to cover more distance in sprinting (p = 0.003) and high-speed running (p < 0.001). Regarding tactical behavior, Structural SSCG stimulated players to explore game space better (p < 0.001). Moreover, Functional SSCG stimulated players to be closer to the ball, decreasing the effective playing space (p = 0.008). We conclude that these strategies of task constraint manipulation impact physical and tactical demands of the game.

Pre- and postoperative in silico biomechanics in individuals with cam morphology during stair tasks.

BACKGROUND: Osteochondroplasty for cam femoroacetabular impingement is a common treatment to improve hip function and prevent joint degeneration. The purpose was to compare in-silico hip biomechanics during stair tasks in pre- and postoperative patients matched with healthy controls. METHODS: Ten symptomatic cam femoroacetabular impingement patients performed stair ascent and descent pre- and 2 years postoperatively. Patients were age, and body-mass-index matched to controls. Full-body kinematics and kinetics were computed and, muscle and hip contact forces were estimated using musculoskeletal modeling and static optimization. Stance-phases were time-normalized and compared using statistical non-parametric mapping. FINDINGS: Preoperatives showed lower hip abduction than controls during stairs ascent (76-100%, P = .007). Pre- and postoperative showed lower hip external rotation compared to controls on stair ascent (Pre-op vs controls: 71-100%, P = .005; Post-op vs controls: 72-100%, P = .01) and stair descent (Pre-op vs controls: 0-62%, P = .001; Post-op vs controls: 0-60%, P = .001). Postoperatives showed lower iliacus force compared to preoperative (1-3%, P = .012) and control (3-6%, P = .008), and higher gluteus maximus and piriformis forces compared to controls during stair descent. Lower postoperative anterior hip contact force (0-7%, P = .004) during descent, and superior (33-35%, P = .018) during ascent compared to controls were observed. Postoperative contact forces were medialized compared to preoperative (0-2%, P = .011) and controls (1-2%, P = .016). INTERPRETATION: Forcing participants to adhere to standardized step length/rise minimized sagittal kinematic differences between conditions and groups. Persistent reduced hip external rotation postoperatively and minor muscle force adaptations led to reduced superior hip contact force during stair ascent and reduced anterior and more medialized contact forces during stair descent.

BOPS: a Matlab toolbox to batch musculoskeletal data processing for OpenSim.

This paper presents Batch OpenSim Processing Scripts (BOPS), a Matlab toolbox for batch processing common OpenSim procedures: Inverse Kinematics, Inverse Dynamics, Muscle Analysis, Static Optimization, and Joint Reaction Analysis. BOPS is an easy-to-use and highly configurable tool that aims to reduce the time required to process large datasets, thus fostering the adoption of musculoskeletal modeling and simulations in daily practice. Its graphical user interface includes pre-defined setup files and has been designed to fulfill the needs of different research projects by simplifying the customization of the procedures, facilitating the analysis, and boosting research group collaborations. BOPS is released under Apache License 2.0, and its source code is freely available on SimTK and GitHub.

Mind-Muscle Connection: Limited Effect of Verbal Instructions on Muscle Activity in a Seated Row Exercise.

Verbal instruction increases electromyographic (EMG) activity in the first three repetitions of an exercise, but its effect on an entire exercise set until failure is unknown. Once there are changes in motor unit recruitment due to fatigue, the effect of verbal instructions can change during different intervals of a set. This study analyzed whether verbal instruction emphasized the contraction of back muscles (i.e., myoelectric activity) during initial, intermediate, and final exercise repetitions performed until failure. Twenty participants with little or no experience in strength training performed a seated row exercise with and without verbal instruction. Surface electrodes were fixed over the latissimus dorsi, teres major, biceps brachii, and posterior deltoid (PD) muscles. Myoelectric activity was computed by mean amplitude and by the median frequency. We analyzed data with repeated measures multivariate analysis of variance and found that, with verbal instruction, there was increased EMG mean amplitude in the latissimus dorsi (15.21%, p = .030) and reduced EMG mean amplitude in the PD (14.39%, p = .018) on initial repetitions. Other muscle EMG amplitudes did not change. On intermediate repetitions, there was reduced signal amplitude only in the PD (15.03%, p = .022). The verbal instruction did not interfere with signal amplitude on final repetitions nor in the median frequency throughout the series. Verbal instruction seems to have little effect on increasing myoelectric activity of these targeted muscles in an entire set of a resistance training.

Validity and reliability of a 6-a-side small-sided game as an indicator of match-related physical performance in elite youth Brazilian soccer players.

The aims of this study were: (i) to compare the external and internal load during a 6-a-side small-sided game (6v6-SSG) according to age-group; (ii) to relate these parameters between the 6v6-SSG and official matches; and (iii) to test the reliability of the 6v6-SSG. A total of 51 Brazilian youth soccer players participated in this study (U11 [n = 16]; U13 [n = 10]; U15 [n = 9]; U17 [n = 8]; U20 [n = 8]). Three experiments were conducted. Experiment A: fifty-one U11 to U20 players were submitted to 6v6-SSGs (n = 10 games; two for each age-group). Experiment B: thirty-two players were randomized to also play official matches (n = 6 matches). Experiment C: thirty-five youth players played the 6v6-SSG twice for test and retest reliability analysis. External load was obtained using Global Positioning Systems and the internal load parameter was calculated through mean heart rate. Statistical approaches showed progressive increases in all parameters according to categories (U11< U13< U15< U17< U20; p < 0.05; ES = 0.42-23.68). Even controlling for chronological age, all parameters showed likely to almost certain correlations between 6v6-SSG and official matches (r = 0.25-0.92). Collectively, the proposed protocol indicates good reliability (CV% = 2.0-12.6; TE% = 2.3-2.7%; ICC = 0.78-0.90). This research suggests that the 6v6-SSG is an alternative tool to indicate match-related physical performance in youth soccer players.

Team Dynamics, Running, and Skill-Related Performances of Brazilian U11 to Professional Soccer Players During Official Matches.

Palucci Vieira, LH, Aquino, R, Moura, FA, Barros, RMLd, Arpini, VM, Oliveira, LdP, Bedo, BLdS, and Pereira Santiago, PR. Team dynamics, running, and skill-related performances of Brazilian U11 to professional soccer players during official matches. J Strength Cond Res 33(8): 2202-2216, 2019-Analyses of movements during soccer competition have been used previously to help develop conditioning programs. However, this has not been extensively studied in youth populations. Therefore, the purposes of this study were to examine (1) dynamics of collective tactical movements, (2) running, and (3) skill-related performances during soccer matches disputed by children to senior players. A total of 120 Brazilian players in the age groups U11, U13, U15, U17, U20, and professional (PRO) were monitored during official competition matches (N = 12). Using semiautomatic video-based tracking (30 Hz), match running variables including total distance traveled, average speed, maximum sprint speed, and high-intensity activities were evaluated. Tactical metrics were computed as team surface area, spread, and median frequency. Through notational analysis, technical skills such as involvements with the ball, passes, ball touches, duels, and goal attempts were also recorded. One-way analysis of variance and magnitude-based inferences were used to detect differences between ages. Although the average speed, team surface area, and spread tended to present stabilized increases from the U15 (e.g., U15 > U13 > U11), maximal sprinting speed (PRO > U17 > U15, U13, U11) and percentage at very high-intensity activities (U20 > PRO, U17 > U15 > U13 > U11) demonstrated continuous gains. Median frequencies were higher in the younger groups (U13, U15, U17 > U20, PRO), although the percentage of successful passes was higher in the older groups (PRO > U17, U15 > U13, U11). We concluded that Brazilian U11 to PRO players present different performance profiles for running, collective movement dynamics, and technical skills, and that the rate of development regarding these components varies. Coaches should be aware of these differences to select and adapt training content for each age group.

Additional Haptic Information Provided by Anchors Reduces Postural Sway in Young Adults Less Than Does Light Touch.

This study investigated the effect of adding haptic information to the control of posture, as well as comparing the effect of both the "light touch" (LT) and "anchor system" (AS) paradigms on postural sway. Additionally, it compared the effect of location and number of points of contact to the control of posture in young adults. The location consisted of using the anchors tied to the finger and held by the hands, and, for LT, the fingertip. For the number of points of contact, participants used two hands, and then separately the dominant hand, and the non-dominant hand, for both anchor and LT paradigms. Participants stood upright with feet-together and in tandem position while performing tasks that combined the use of anchors and LT, points of contact (hand grip and finger), and number of points of contact (two hands and one hand). In this study, the anchors consist of holding in each hand a flexible cable with the other end attached to the ground. The LT consists of slightly touching a rigid surface with the tip of the index finger. The results showed, first, that the anchors improved postural control less than did the LT. Second, they revealed that holding the anchors with the hands or with them tied to the fingertip resulted in a similar reduction in postural sway only in the tandem position. For the feet-together position, the anchors tied to the fingertip were ineffective. Similarly, the use of one or two hands did not affect the contribution of the anchors. However, using two hands in the LT condition was more effective than was one hand. Third, our results showed the presence of a temporal delay between force and center-of-pressure (COP) for the anchors, only in the AP direction with feet-together. In conclusion, overall, the anchors were less effective in reducing postural sway than was the LT. The anchors attached to fingertips were as effective as the hand-held anchors in the tandem position, yet ineffective during foot-together standing. Force-COP timing explains reduced postural sway with LT but not for the anchor; hence, exploratory and supra-postural components may be involved.

Kicking Performance in Young U9 to U20 Soccer Players: Assessment of Velocity and Accuracy Simultaneously.

PURPOSE: The purpose of this study was to compare the kicking performance of young soccer players in the U9 to U20 age groups. METHOD: Three hundred and sixty-six Brazilian players were evaluated on an official pitch using three-dimensional kinematics to measure (300 Hz) ball velocity (Vball), foot velocity (Vfoot), Vball/Vfoot ratio, last stride length, and distance between the support foot and the ball. Simultaneously, a two-dimensional procedure was also conducted to compute (60 Hz) the mean radial error, bivariate variable error, and accuracy. Possible age-related differences were assessed through one-way analysis of variance and magnitude-based inferences. RESULTS: Ball velocity increased by 103% (p < .001, η2 = .39) from the U11 age group (48.54 ± 8.31 km/hr) to the U20 age group (98.74 ± 16.35 km/hr). Foot velocity presented a 59% increase (p < .001, η2 = .32) from the U11 age group (49.08 ± 5.16 km/hr) to U20 (78.24 ± 9.49 km/hr). This finding was due to improvement in the quality of foot-ball impact (Vball/Vfoot ratio) from U11 (0.99 ± 0.13 a.u.) to U20 (1.26 ± 0.11 a.u.; p < .001, η2 = .25). Parameters such as mean radial error and accuracy appeared to be impaired during the growth spurt (U13-U15). Last stride length was correlated, low to moderately high, with Vball in all age groups (r = .36-.79). CONCLUSIONS: In summary, we concluded that simple biomechanical parameters of kicking performance presented distinct development. These results suggest that different training strategies specific for each age group could be applied. We provide predictive equations to aid coaches in the long-term monitoring process to develop the kick in soccer or search for talented young players.

Probing the antioxidant potential of phloretin and phlorizin through a computational investigation.

The structures and energetics of two dihydrochalcones (phloretin and its glycoside phlorizin) were examined with density functional theory, using the B3LYP, M06-2X, and LC-ω PBE functionals with both the 6-311G(d,p) and 6-311 + G(d,p) basis sets. Properties connected to antioxidant activity, i.e., bond dissociation enthalpies (BDEs) for OH groups and ionization potentials (IPs), were computed in a variety of environments including the gas-phase, n-hexane, ethanol, methanol, and water. The smallest BDEs among the four OH groups for phloretin (three for phlorizin) were determined (using B3LYP/6-311 + G(d,p) in water) to be 79.36 kcal/mol for phloretin and 79.98 kcal/mol for phlorizin while the IPs (at the same level of theory) were obtained as 139.48 and 138.98 kcal/mol, respectively. By comparing with known antioxidants, these values for the BDEs indicate both phloretin and phlorizin show promise for antioxidant activity. In addition, the presence of the sugar moiety has a moderate (0-6 kcal/mol depending on functional) effect on the BDEs for all OH groups. Interestingly, the BDEs suggest that (depending on the functional chosen) the sugar moiety can lead to an increase, decrease, or no change in the antioxidant activity. Therefore, further experimental tests are encouraged to understand the substituent effect on the BDEs for phloretin and to help determine the most appropriate functional to probe BDEs for dihydrochalcones.

Biomechanical analysis of the shoulder of swimmers after a maximal effort test.

OBJECTIVES: To compare the kinematics and electromyography of the periscapular muscles in swimmers before and after a 3-min maximal effort test. PARTICIPANTS: 16 competitive swimmers. MAIN OUTCOME MEASUREMENTS: Infrared cameras were used to record kinematics in the scapular plane in synchronization with the electromyography system. RESULTS: There was an increase in internal rotation in all angles (p < 0.05), an increase of the anterior tilt, with 120° of elevation (p = 0.04). The serratus anterior showed a decrease in the intervals of 120-90° and 60-30° (p = 0.04; p = 0.02). There was a linear relationship between the variation before and after the maximal effort of the anterior tilt in relation to the variation of muscular activation of the transverse trapezius (p = 0.01) and the lower trapezius (42%, p = 0.01); an internal rotation in 120° and 90° of elevation in relation to the transverse trapezius (p = 0.01); and an internal rotation in 60° and 30° of elevation in relation to the serratus anterior (p = 0.04, p = 0.03). CONCLUSION: A maximal 3-min effort test resulted in altered scapular biomechanics. More studies are needed to verify if the changes correspond to a risk factor for injuries.

Effects of match situational variables on possession: the case of England Premier League season 2015/16

Aim: The main aim of this study was to identify the effects of match location, quality of opponents and match status on possession during the 2015/16 Season of England Premier League. Methods: Three hundred and eighty matches played by 20 teams were analysed. For each match, two values were recorded, resulting in 760 observations. Results Teams who played at home (51.77 ± 10.22%) presented higher possession values (EF=moderate) than those who played away (48.21 ± 10.30%). Quality of opponents also had a significant difference, as possession was higher (EF=large) when teams played against weak (52.30 ± 9.77%) than strong opponents (46.48 ± 10.38%). The multivariate analysis revealed no interaction between situational variables and possession (p = 0.76). Despite the teams classified as "best-ranking" (1st to 8th position: 50.60 ± 10.35%) presented greater possession (EF=moderate) than "worst-ranking" (9st to 20th position: 47.59 ± 9.74%), no significant differences were found in the comparisons of match status (winner [50.34 ± 10.48%] x drawer [49.95 ± 10.25%] x loser [49.68 ± 10.48%]). Conclusion: General interpretations should be viewed with caution, since this possession can represent an indicator of success for a team but not for others.(AU)

Effect of Low-Power Laser (LPL) and Light-Emitting Diode (LED) on Inflammatory Response in Burn Wound Healing.

The aim of the study was to investigate the biochemical and molecular changes in the process of epidermal healing of burn injuries after therapeutic treatment with low-power laser (LPL) and light-emitting diode (LED). Rats were divided into six groups: skin without injury (Sham), burn wounds (BWs), BW + 660-nm LPL, BW + 904-nm LPL, BW + 632-nm LED, and BW + 850-nm LED. The burn wound model was performed using a 100 °C copper plate, with 10 s of contact in the skin. The irradiations started 24 h after the lesion and were performed daily for 7 days. The burn wound groups showed an increase in the superoxide production, dichlorofluorescein, nitrites, and high protein oxidative damage. The activities of glutathione peroxidase and catalase were also increased, and a significant reduction in glutathione levels was observed compared to the control group. However, treatments with 660-nm LPL and 850-nm LED promoted protection against to oxidative stress, and similar results were also observed in the IL-6 and pERK1/2 expression. Taken together, these results suggest that LPL 660 nm and LED 850 nm appear reduced in the inflammatory response and oxidative stress parameters, thus decreasing dermal necrosis and increasing granulation tissue formation, in fact accelerating the repair of burn wounds.

The Effect of Ursolic Acid on Leishmania (Leishmania) amazonensis Is Related to Programed Cell Death and Presents Therapeutic Potential in Experimental Cutaneous Leishmaniasis.

Among neglected tropical diseases, leishmaniasis is one of the most important ones, affecting more than 12 million people worldwide. The available treatments are not well tolerated, and present diverse side effects, justifying the search for new therapeutic compounds. In the present study, the activity of ursolic acid (UA) and oleanolic acid (OA) were assayed in experimental cutaneous leishmaniasis (in vitro and in vivo). Promastigote forms of L. amazonensis were incubated with OA and UA for 24h, and effective concentration 50% (EC50) was estimated. Ultraestructural alterations in Leishmania amazonensis promastigotes after UA treatment were evaluated by transmission electron microscopy, and the possible mode of action was assayed through Annexin V and propidium iodide staining, caspase 3/7 activity, DNA fragmentation and transmembrane mitochondrial potential. The UA potential was evaluated in intracellular amastigotes, and its therapeutic potential was evaluated in L. amazonensis infected BALB/c mice. UA eliminated L. amazonensis promastigotes with an EC50 of 6.4 µg/mL, comparable with miltefosine, while OA presented only a marginal effect on promastigote forms at 100 µg/mL. The possible mechanism by which promastigotes were eliminated by UA was programmed cell death, independent of caspase 3/7, but it was highly dependent on mitochondria activity. UA was not toxic for peritoneal macrophages from BALB/c mice, and it was able to eliminate intracellular amastigotes, associated with nitric oxide (NO) production. OA did not eliminate amastigotes nor trigger NO. L. amazonensis infected BALB/c mice submitted to UA treatment presented lesser lesion size and parasitism compared to control. This study showed, for the first time, that UA eliminate promastigote forms through a mechanism associated with programed cell death, and importantly, was effective in vivo. Therefore, UA can be considered an interesting candidate for future tests as a prototype drug for the treatment of cutaneous leishmaniasis.

Treadmill training increases SIRT-1 and PGC-1 α protein levels and AMPK phosphorylation in quadriceps of middle-aged rats in an intensity-dependent manner.

The present study investigated the effects of running at 0.8 or 1.2 km/h on inflammatory proteins (i.e., protein levels of TNF- α , IL-1 ß , and NF- κ B) and metabolic proteins (i.e., protein levels of SIRT-1 and PGC-1 α , and AMPK phosphorylation) in quadriceps of rats. Male Wistar rats at 3 (young) and 18 months (middle-aged rats) of age were divided into nonexercised (NE) and exercised at 0.8 or 1.2 km/h. The rats were trained on treadmill, 50 min per day, 5 days per week, during 8 weeks. Forty-eight hours after the last training session, muscles were removed, homogenized, and analyzed using biochemical and western blot techniques. Our results showed that: (a) running at 0.8 km/h decreased the inflammatory proteins and increased the metabolic proteins compared with NE rats; (b) these responses were lower for the inflammatory proteins and higher for the metabolic proteins in young rats compared with middle-aged rats; (c) running at 1.2 km/h decreased the inflammatory proteins and increased the metabolic proteins compared with 0.8 km/h; (d) these responses were similar between young and middle-aged rats when trained at 1.2 km. In summary, the age-related increases in inflammatory proteins, and the age-related declines in metabolic proteins can be reversed and largely improved by treadmill training.

MG2 and lactoferrin form a heterotypic complex in salivary secretions.

Protein-protein interactions are necessary for homeostasis to be maintained and for biological systems to be integrated. Heterotypic complexes occur in saliva, and a complex between MG2 and SIgA has been suggested to promote microbial clearance from the oral cavity. In this study, we used a peptide display library to investigate previously unrecognized heterotypic complexes involving MG2 and other proteins. The library was panned with MG2 12 times, and analyses of clones identified the sequence Ala-Leu-Leu-Cys-, which occurs in salivary lactoferrin. Blotting experiments confirmed that MG2 and lactoferrin form a heterotypic complex in vitro and in vivo. Periodate treatment of MG2 did not affect the interaction. A synthetic lactoferrin peptide containing the motif Ala-Leu-Leu-Cys-blocked the interaction between MG2 and lactoferrin, confirming the specificity of the interaction identified by panning. This complex may enhance the properties of these salivary components in the oral environment.