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1.
Bioorg Med Chem Lett ; : 127022, 2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-32063431

RESUMO

TRPV4 is a ubiquitously expressed, non-selective cation channel activated by a range of stimuli including hypotonicity, temperature, pH, stretch and endogenous ligands. Agents that modulate TRPV4 are sought as potential therapeutics for the treatment of many diseases including osteoarthritis, respiratory illnesses, gastrointestinal disorders, pain and congestive heart failure. In recent years, significant advances in TRPV4 drug discovery have been realized as at least seven novel TRPV4 agonist or antagonist templates were reported and the first selective TRPV4 antagonist was evaluated in early clinical trials.

2.
J Strength Cond Res ; 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32032233

RESUMO

O'Grady, MW, Young, WB, Behm, DG, and Talpey, SW. Effect of intention to squat explosively on acute countermovement jump performance. J Strength Cond Res XX(X): 000-000, 2020-The purpose of this study was to investigate the influence of squatting with the intention of moving the bar as fast as possible during the ascent phase on potentiating countermovement jump (CMJ) performance. Fourteen recreationally resistance-trained men (age = 22.1 ± 1.7 years, height = 179.9 ± 4.2 cm, body mass = 83.8 ± 6.6 kg) with a predicted 1 repetition maximum half-squat of 201.0 ± 27.8 kg participated in this study. Subjects performed 3 CMJs before and then 4 and 8 minutes after a squat conditioning activity (CA). Conditions were randomized. For 1 condition, the CA involved subjects performing 4 repetitions of the half-squat with a 5RM load in a controlled manner (CON) at a self-selected normal squatting tempo. In the other condition, subjects used the same number of repetitions and load; however, they were instructed to move the bar up as fast as possible during the concentric phase of the half-squat (VMAX). Half-squat peak force (N), peak power (W), peak velocity (m·s), and rate of force development (RFD) were measured for each CA using a force platform and linear position transducer. At 4 and 8 minutes post-CA, CMJ height, relative peak power, peak velocity, and peak force were also measured. Despite there being significant increases in the half-squat peak power, peak velocity and maximum RFD in the VMAX condition, neither condition significantly improved any post-CMJ variable. Some small improvements in jump height were observed in certain individuals after the VMAX condition, suggesting that an explosive half-squat CA may potentiate CMJ performance in certain individuals.

3.
Artigo em Inglês | MEDLINE | ID: mdl-32034819

RESUMO

The aim of this scoping review was i) to update a previous review on the main methodological characteristics and shortcomings in the plyometric jump training (PJT) literature, and ii) to recommend, in light of the identified methodological gaps, future research perspectives. We searched four electronic databases. From 6,128 potentially relevant articles, 420 were considered eligible for inclusion. As an update of a previous review, this represents an increase of ~200 articles, illustrating that this field of research is growing fast. However, the relative "quality" or shortcomings were similar when compared to the preceding scoping review. In the current article, the main identified shortcomings were an insufficient number of studies conducted with females, individual sports, and high-level athletes (~22%, ~7%, and ~14% of overall studies, respectively); insufficient description of training prescription (~54% of studies); and studies missing an active/passive control group and a randomised group allocation process (~37% and ~24% of overall studies, respectively). Furthermore, PJT was often combined with other training methods and added to the participants' regular training routines (~50% and ~35% of overall studies, respectively). The main outcomes of this scoping review urge researchers to conduct PJT studies of high methodological quality (e.g., randomised controlled trials) to get trustworthy evidence-based knowledge. In addition, owing to the limited research conducted with females, individual sports, and high-level athletes, more studies are needed to substantiate the available findings. Finally, the identification of cohort-specific PJT dose-response relations which elicit optimal training effects still need to be identified, particularly in the long term.

4.
Sports Med ; 50(2): 387-402, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31628662

RESUMO

BACKGROUND: Foam rolling (FR) has been demonstrated to acutely enhance joint range of motion (ROM). However, data syntheses pooling the effect sizes across studies are scarce. It is, furthermore, unknown which moderators affect the treatment outcome. OBJECTIVE: To quantify the immediate effects of FR on ROM in healthy adults. METHODS: A multilevel meta-analysis with a robust random effects meta-regression model was used to pool the standardized mean differences (SMD) between FR and no-exercise (NEX) as well as FR and stretching. The influence of the possible effect modifiers treatment duration, speed, targeted muscle, testing mode (active/passive ROM), sex, BMI, and study design was examined in a moderator analysis. RESULTS: Twenty-six trials with high methodological quality (PEDro scale) were identified. Compared to NEX, FR had a large positive effect on ROM (SMD: 0.74, 95% CI 0.42-1.01, p = 0.0002), but was not superior to stretching (SMD: - 0.02, 95% CI - 0.73 to 0.69, p = 0.95). Although the few individual study findings suggest that FR with vibration may be more effective than NEX or FR without vibration, the pooled results did not reveal significant differences (SMD: 6.75, 95% CI - 76.4 to 89.9, p = 0.49 and SMD: 0.66, 95% CI - 1.5 to 2.8, p = 0.32). According to the moderator analysis, most potential effect modifiers (e.g., BMI, speed or duration) do not have a significant impact (p > 0.05) but FR may be less effective in men (p < 0.05). CONCLUSION: FR represents an effective method to induce acute improvements in joint ROM. The impact of moderators should be further elucidated in future research.

5.
J Sports Sci Med ; 18(4): 789-797, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31827364

RESUMO

The objective was to investigate the effects of functional (FT) and traditional (TT) training on trunk muscles maximal isometric strength, rate of force development and endurance with trained elderly women. Forty-five elderly women were directed into three groups: FT (n =1 6), TT (n = 14) and Control (n = 15). The FT (multi-planar, and multi-articular movements) and TT (primarily machine-based resistance exercises) performed mobility, muscle strength and power exercises. Both training groups also performed intermittent cardiometabolic activities. The maximum strength and endurance of the trunk muscles were verified, both at baseline and after 12 weeks of training (3xweek for 50 min each). Data were analyzed using a 2-way ANCOVA with contrast of adjusted mean values. FT significantly increased all variables: maximum trunk flexor strength (p = 0.002, 22%); rate of flexor force development (p = 0.001, 84%); trunk extensors maximal strength (p = 0.003, 17%); trunk extensor rate of force development (p = 0.05, 16%); trunk flexors (p = 0.001, 19%) and extensors (p = 0.017, 13%) endurance compared to baseline. TT showed an increase only in RFD of trunk extensors (p = 0.003, 53%), and flexors (p = 0.033, 42%), and trunk flexors endurance (p = 0.008, 11%). However, there was no statistically significant difference between groups. FT promoted improvement in all variables; strength, endurance and rate of force development of the trunk flexors and extensors of the elderly. On the other hand, TT improved only the rate of force development of trunk flexors and extensors and endurance of the trunk flexors. FT is recommended for elderly women as it improves a broader array of physiological parameters.

6.
Pediatr Exerc Sci ; : 1-12, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31653801

RESUMO

PURPOSE: Whereas cross-education has been extensively investigated with adults, there are far fewer youth investigations. Two studies suggested that children had greater global responses to unilateral knee extensor fatigue and training, respectively, than adults. The objective of this study was to compare global training responses and cross-education effects after unilateral elbow flexion (EFlex) and leg press (LP) training. METHODS: Forty-three prepubertal youths (aged 10-13 y) were randomly allocated into dominant LP (n = 15), EFlex (n = 15) training groups, or a control (n = 13). Experimental groups trained 3 times per week for 8 weeks and were tested pretraining and posttraining for ipsilateral and contralateral 1-repetition maximum LP; knee extensor, knee flexors, elbow flexors; and handgrip maximum voluntary isometric contractions (MVIC), and countermovement jump. RESULTS: In comparison to no significant changes with the control group, dominant elbow flexors training demonstrated significant ( P < .001) improvements only with ipsilateral and contralateral upper body testing (EFlex MVIC [15.9-21.5%], EFlex 1-repetition maximum [22.9-50.8%], handgrip MVIC [5.5-13.8%]). Dominant LP training similarly exhibited only significant ( P < .001) improvements for ipsilateral and contralateral lower body testing (LP 1-repetition maximum [59.6-81.8%], knee extensor MVIC [12.4-18.3%], knee flexor MVIC [7.9-22.3%], and countermovement jump [11.1-18.1%]). CONCLUSIONS: The ipsilateral and contralateral training adaptations in youth were specific to upper or lower body training, respectively.

7.
J Sport Rehabil ; : 1-9, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31648203

RESUMO

CONTEXT: Stretching intensity is an important variable that can be manipulated with flexibility training. However, there is a lack of evidence regarding this variable and its prescription in stretching programs. OBJECTIVE: To investigate the effects of 12 weeks of knee flexor static stretching at different intensities on joint and muscle mechanical properties. DESIGN: A randomized clinical trial. SETTING: Laboratory. PARTICIPANTS: A total of 14 untrained men were allocated into the low- or high-intensity group. MAIN OUTCOME MEASURES: Assessments were performed before, at 6 week, and after intervention (12 wk) for biceps femoris long head architecture (resting fascicle length and angle), knee maximal range of motion (ROM) at the beginning and maximal discomfort angle, knee maximal tolerated passive torque, joint passive stiffness, viscoelastic stress relaxation, knee passive torque at a given angle, and affective responses to training. RESULTS: No significant differences were observed between groups for any variable. ROM at the beginning and maximal discomfort angle increased at 6 and 12 weeks, respectively. ROM significantly increased with the initial angle of discomfort (P < .001, effect size = 1.38) over the pretest measures by 13.4% and 14.6% at the 6- and 12-week assessments, respectively, and significantly improved with the maximal discomfort angle (P < .001, effect size = 1.25) by 15.6% and 18.8% from the pretest to the 6- and 12-week assessments, respectively. No significant effects were seen for muscle architecture and affective responses. Initial viscoelastic relaxation for the low-intensity group was lower than ending viscoelastic relaxation. CONCLUSION: These results suggest that stretching with either low or high discomfort intensities are effective in increasing joint maximal ROM, and that does not impact on ROM, stiffness, fascicle angle and length, or affective response differences.

8.
J Med Chem ; 62(20): 9270-9280, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31532662

RESUMO

GSK3527497, a preclinical candidate for the inhibition of TRPV4, was identified starting from the previously reported pyrrolidine sulfonamide TRPV4 inhibitors 1 and 2. Optimization of projected human dose was accomplished by specifically focusing on in vivo pharmacokinetic parameters CLu, Vdssu, and MRT. We highlight the use of conformational changes as a novel approach to modulate Vdssu and present results that suggest that molecular-shape-dependent binding to tissue components governs Vdssu in addition to bulk physicochemical properties. Optimization of CLu within the series was guided by in vitro metabolite identification, and the poor FaSSIF solubility imparted by the crystalline properties of the pyrrolidine diol scaffold was improved by the introduction of a charged moiety to enable excellent exposure from high crystalline doses. GSK3527497 is a preclinical candidate suitable for oral and iv administration that is projected to inhibit TRPV4 effectively in patients from a low daily clinical dose.

9.
J Hum Kinet ; 67: 5-15, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31523302

RESUMO

Investigations of trunk strength with high-level athletes are limited. The purpose of this study was to compare maximal concentric isokinetic trunk extension and flexion torque, power, and strength ratios between high-level weightlifters (n = 20), wrestlers (n = 20) and a control (n = 25) population. Isokinetic dynamometry was used to evaluate peak torque, power and strength ratios during seated trunk extension/flexion actions at 60°/s and 180°/s. There were no significant anthropometric differences between groups. Overall, trunk isokinetic force variables as a function of the increase in angular velocity, showed a decrease in peak torque, but an increase in power (athletes and controls). Compared to the control group, athletes demonstrated significantly higher trunk extension torque (+67.05 N·m, ES = 0.81) and power (+49.28 N·m, ES = 0.82) at 60°/s and 180°/s, respectively. Athletes produced significantly greater trunk flexion-extension ratios at 60°/s and 180°/s (ES = 0.80-0.47) than controls. Weightlifters and wrestlers exhibited significantly higher extensor than flexor torque at all angular velocities. Weightlifters demonstrated greater torque (ES = 0.79) than wrestlers at 60°/s. The wrestlers' average power was significantly higher (ES = 0.43) than weightlifters at 180°/s. There were no significant ratio differences between wrestlers (66.23%) and weightlifters (72.06%). Weightlifters had stronger extensor muscles at 60°/s, whereas wrestlers had higher power at 180°/s for extensor muscles. It was postulated that the extensor muscles were stronger than the flexors to ensure trunk stabilisation, and for prevention of injuries. These differences seem to be associated to the movements that occur in each sport in terms of both muscle actions and contractile forces.

10.
Int J Sports Med ; 40(12): 779-788, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31487749

RESUMO

Static stretching (SS) can increase joint range of motion (ROM), due to neural, morphological, and physio-psychological factors. Periodized training programs (PD) (e. g., strength, power) are adopted to induce greater adaptations while avoiding overtraining. However, the effectiveness of periodized stretch training adaptations are unknown. Therefore, the objective of this study was to compare the effects of periodized and non-periodized (NP) stretching programs on flexibility, hamstrings stiffness and muscle performance. Sixteen gymnasts were allocated to either periodized or non-periodized SS training and tested pre- and post-8 weeks for countermovement jump height, hip flexors, hip extensors and dorsiflexors ROM, hamstrings stiffness and hamstrings and quadriceps peak torque. Both stretch training groups significantly and similarly increased hip extensor (33.2%), hip flexor (25.2%), and dorsiflexor (23.8%) ROM, hamstrings peak torque (7.9%) and jump height (8.1%) from pre - to post- training. Both groups decreased hamstrings stiffness across the last ten angles (32.1%). PD elicited consistently large magnitude flexibility effect size changes compared to small and moderate magnitude changes for the non-periodized. Therefore, 8-week PD and NP SS programs can decrease young gymnasts' muscle-tendon stiffness and increase muscle performance. However, effect sizes indicate that PD stretch training was more advantageous to increasing flexibility and improving performance.


Assuntos
Desempenho Atlético/fisiologia , Ginástica/fisiologia , Exercícios de Alongamento Muscular/métodos , Músculo Esquelético/fisiologia , Criança , Elasticidade , Teste de Esforço/métodos , Feminino , Músculos Isquiotibiais/fisiologia , Articulação do Quadril/fisiologia , Humanos , Músculo Quadríceps/fisiologia , Amplitude de Movimento Articular/fisiologia , Torque
11.
ACS Med Chem Lett ; 10(8): 1228-1233, 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31413810

RESUMO

GSK2798745, a clinical candidate, was identified as an inhibitor of the transient receptor potential vanilloid 4 (TRPV4) ion channel for the treatment of pulmonary edema associated with congestive heart failure. We discuss the lead optimization of this novel spirocarbamate series and specifically focus on our strategies and solutions for achieving desirable potency, rat pharmacokinetics, and physicochemical properties. We highlight the use of conformational bias to deliver potency and optimization of volume of distribution and unbound clearance to enable desirable in vivo mean residence times.

12.
Front Physiol ; 10: 1026, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31447705

RESUMO

The purpose of this study was to compare the effects of combined resistance and plyometric/sprint training with plyometric/sprint training or typical soccer training alone on muscle strength and power, speed, change-of-direction ability in young soccer players. Thirty-one young (14.5 ± 0.52 years; tanner stage 3-4) soccer players were randomly assigned to either a combined- (COMB, n = 14), plyometric-training (PLYO, n = 9) or an active control group (CONT, n = 8). Two training sessions were added to the regular soccer training consisting of one session of light-load high-velocity resistance exercises combined with one session of plyometric/sprint training (COMB), two sessions of plyometric/sprint training (PLYO) or two soccer training sessions (CONT). Training volume was similar between the experimental groups. Before and after 7-weeks of training, peak torque, as well as absolute and relative (normalized to torque; RTD r ) rate of torque development (RTD) during maximal voluntary isometric contraction of the knee extensors (KE) were monitored at time intervals from the onset of contraction to 200 ms. Jump height, sprinting speed at 5, 10, 20-m and change-of-direction ability performances were also assessed. There were no significant between-group baseline differences. Both COMB and PLYO significantly increased their jump height (Δ14.3%; ES = 0.94; Δ12.1%; ES = 0.54, respectively) and RTD at mid to late phases but with greater within effect sizes in COMB in comparison with PLYO. However, significant increases in peak torque (Δ16.9%; p < 0.001; ES = 0.58), RTD (Δ44.3%; ES = 0.71), RTD r (Δ27.3%; ES = 0.62) and sprint performance at 5-m (Δ-4.7%; p < 0.001; ES = 0.73) were found in COMB without any significant pre-to-post change in PLYO and CONT groups. Our results suggest that COMB is more effective than PLYO or CONT for enhancing strength, sprint and jump performances.

13.
J Sports Sci Med ; 18(3): 544-551, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31427877

RESUMO

Currently there are recommendations for stretching type, repetitions and duration within a training session to improve flexibility. It is, however, unclear whether multiple daily stretch training sessions provide greater flexibility than single daily sessions. The objective was to investigate the effectiveness of single (1×day) versus twice daily (2×day) unilateral stretch training sessions on hip flexion range of motion (ROM), agonist and antagonist force and jump performance of the stretched and contralateral, non-stretched legs. Groups included a control, 1×day and 2×day stretch training groups. Static stretching (SS) involved self-administered (stretch band), unilateral, hamstrings and quadriceps stretching for 2-weeks. Pre- and post-testing involved hip flexion ROM, knee extension and flexion maximal voluntary isometric contraction (MVIC) forces and unilateral drop jumps (DJ). The 2×day group showed a 12.8% (p = 0.08) greater active ROM versus Control. The 1×day group showed a 7.5% (p=0.1) ballistic ROM increase with no significant changes with the 2×day and Control groups. The stretched leg experienced a 5.01% (p = 0.1) hip flexion ballistic ROM increase contrasting with a 2.3% increase for the contralateral leg. Twice daily training provided 7.1% (p = 0.07) and 6.6% (p = 0.01) quadriceps MVC force increases of the stretched trained and contralateral legs respectively. Contralateral DJ height improved 22.6% (p = 0.002) with 2×day training. In conclusion, 1xday and 2×day stretch training tended to improved ballistic and active ROM respectively, whereas 2×day training improved MVIC force and DJ height. The findings may apply to fitness enthusiasts and rehabilitation as unilateral stretching may retain performance and active ROM of the stretched and contralateral limbs.

14.
J Sports Sci Med ; 18(3): 552-558, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31427878

RESUMO

Increased stretch tolerance can contribute to improved range of motion (ROM). Since menthol-based topical analgesics (TopAnalg) suppress pain, they may increase stretch thresholds improving ROM. Other modalities such as transcutaneous electrical nerve stimulation and rolling have demonstrated decreased pain sensitivity in the contralateral limb. The purpose of this study was to investigate the effects of a TopAnalg on active and passive ROM of the treated and contralateral (untreated) leg. With a double blind, repeated measures design, 14 university students had a TopAnalg or a placebo gel applied to their hamstrings, rested for 20-min and then either performed static or dynamic stretching. Prior to gel application and after stretching, participants were tested for passive static, active and ballistic hip flexion ROM. Near significant greater ballistic hip flexion ROM for both legs (treated: p = 0.08; 3.6%; contralateral: p = 0.1; 1.6%) were observed with the TopAnalg. With dynamic stretching, ballistic hip flexion ROM of both limbs at post-test (p=0.01-0.007; 3.3-4.2%) and post-10 minutes (p = 0.06-0.01; 2.7-4.1%) decreased with the placebo, whereas there were no significant reductions with the TopAnalg. There was a near significant higher active hip flexion ROM (stretched leg: p = 0.05; 4.6%), and significantly higher ballistic hip flexion ROM (p = 0.04-0.05; 3.4-3.5%) with static versus dynamic stretching for both legs. In conclusion, TopAnalg can increase hip flexion ROM of the treated and contralateral limbs. Secondly, static stretching contributed to greater ballistic ROM in both the stretched and non-stretched contralateral limbs. Hence, TopAnalg may be used to enhance flexibility training with rehabilitation or highly trained athletes.

15.
Sports Biomech ; : 1-10, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31464179

RESUMO

The manipulation of the volume and intensity of static stretching (SS) can affect the range of motion (ROM) and muscle force output. The purpose of this study was to investigate the effect of two different SS protocols with different intensities (50% and 85% POD) and volumes (120-s and 240-s) on ROM, peak force, and muscle activity during maximal isometric leg curl exercise in well-trained participants. Fifteen young males (age:27.5 ± 6.1years, height:175.6 ± 4.7cm, and body mass:81.5 ± 10.4kg, 6 ± 2 years of resistance training experience) performed passive hip flexion with two different SS protocols: six stretches of 40-s, with 15-sec rest between each stretch at 50% of the point of discomfort (POD) and three stretches of 40-s, with 15-sec rest between each stretch at 85%POD. The passive hip flexion ROM, biceps femoris muscle activation (integrated electromyography: IEMG), and knee flexors force were monitored during a 3-s maximal voluntary isometric leg curl exercise. ROM increased between pre- and post-intervention for both SS protocols (50%POD: p = 0.016, Δ% = 4.6% and 85%POD: p < 0.001, Δ% = 11.42%). Peak force decreased between pre- and post-intervention only for 85%POD (p = 0.004, Δ% = 23.6%). There were no significant IEMG differences. In conclusion, both SS protocols increased ROM, however, the high-intensity and short-duration SS protocol decreased peak force.

16.
Scand J Med Sci Sports ; 29(11): 1805-1812, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31273863

RESUMO

OBJECTIVE: To evaluate the effects of 24 weeks of strength training on stable (ST) and unstable surfaces (UST) on the functional mobility, balance, and concern about falling in healthy older adults, younger than 70. DESIGN: A single-center randomized clinical trial. PARTICIPANTS: Sixty-four older adults (58 females and 6 males; 68 years) were randomized into control, ST, or UST groups. INTERVENTIONS: Both ST and UST intervention groups received a core muscle, upper, and lower limb moderate-intensity strength exercises using stable and unstable surfaces. The classes were performed three times per week over a 24-week period. The control group did not receive any type of active intervention. MEASUREMENTS: The primary outcome measures were the dynamic balance (Berg Balance Scale (BBS)) and functional mobility (timed up and go (TUG) test). The secondary outcomes included the sitting and rising test (SRT) and Falls Efficacy Scale-International (FESI) scores. RESULTS: There was a significant improvement in balance performance (BBS = +4 points) after 24 weeks of both ST (+1.22; 95% CI, -0.19 to 2.63) and UST (+2.26; 95% CI, 0.83-3.70) compared with the control group. Additionally, compared with the control, only UST experienced functional mobility gains (TUG = -2.44; 95% CI, -4.41 to -0.48; SRT = +1.12; 95% CI, 0.08-2.17) and decreased concern about falling (FESI = -4.41; 95% CI, -9.30 to -0.27). CONCLUSION: Long-term ST with and without unstable devices was effective to improve dynamic balance in older adults. Furthermore, the effects of UST were extended to functional mobility gains and reduced concern about falling.

17.
Sports Med ; 49(8): 1173-1181, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31256353

RESUMO

The term "self-myofascial release" is ubiquitous in the rehabilitation and training literature and purports that the use of foam rollers and other similar devices release myofascial constrictions accumulated from scar tissue, ischaemia-induced muscle spasms and other pathologies. Myofascial tone can be modulated with rollers by changes in thixotropic properties, blood flow, and fascial hydration affecting tissue stiffness. While rollers are commonly used as a treatment for myofascial trigger points, the identification of trigger points is reported to not be highly reliable. Rolling mechanisms underlying their effect on pain suppression are not well elucidated. Other rolling-induced mechanisms to increase range of motion or reduce pain include the activation of cutaneous and fascial mechanoreceptors and interstitial type III and IV afferents that modulate sympathetic/parasympathetic activation as well as the activation of global pain modulatory systems and reflex-induced reductions in muscle and myofascial tone. This review submits that there is insufficient evidence to support that the primary mechanisms underlying rolling and other similar devices are the release of myofascial restrictions and thus the term "self-myofascial release" devices is misleading.

19.
J Sports Sci Med ; 18(2): 301-315, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31191101

RESUMO

Post-activation potentiation (PAP) conditioning has been reported to increase performance. Most research has examined PAP effects on strength/power activities, whereas the effects on endurance sports are understudied. The aim of this study was to characterize PAP conditioning stimulus effects on a subsequent 5x1 km running trial. A randomized, within subjects, repeated measures study utilized 12 male, endurance-trained athletes, who performed a full warm-up, conditioning exercise intervention (4x5 repetition maximum band-resisted squat jumps) or a control condition prior to a 5x1 km time trial run. Tests were conducted immediately prior to the intervention, after each kilometer, immediately following the 5x1 km run, and at seven and ten minutes post 5 km run. Measures included the interpolated twitch technique (ITT), evoked contractile properties, maximum voluntary isometric contractions (MVIC) plantar flexor force, drop jump, rating of perceived exertion, and heart rate. The PAP stimulus reduced the time to complete the run (3.6%; p = 0.07, d = 0.51), and decreased the time to complete kilometer one (8%; d = 1.08, p = 0.014). Jump height (p = 0.02; 9.2%) and reactive strength index (p = 0.035; 16%) increased with PAP. F100 (force produced in the first 100ms of the MVIC) and MVIC force with PAP increased at kilometers 3 (p = 0.04, d=0.84), 4 (p = 0.034, d = 0.29), and 7min post-run (p = 0.03, d = 0.60). Voluntary activation (ITT) increased at 7min post-run (p = 0.04, d = 0.59) with PAP, yet decreased at 7min post-run in the control condition (p = 0.03, d = 0.36). A prior band-resisted squat protocol decreased running time and improved neuromuscular properties in endurance athletes running 5x1 km.


Assuntos
Desempenho Atlético/fisiologia , Resistência Física , Corrida/fisiologia , Exercício de Aquecimento , Adulto , Atletas , Eletromiografia , Humanos , Contração Isométrica , Masculino , Músculo Esquelético/fisiologia , Postura
20.
Eur J Appl Physiol ; 119(9): 1943-1949, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31236670

RESUMO

PURPOSE: Prolonged static stretching (SS) in isolation (no dynamic warm-up) can impair muscle performance. There are conflicting reports whether impairments are present in antagonist and contralateral muscles. The objective of this study was to assess the effect of unilateral hamstrings SS on ipsilateral stretched and contralateral limbs' strength and jump power. METHODS: The SS (four repetitions of 30-s) and control sessions involved unilateral testing of the stretched leg and contralateral leg for knee extension (KE) maximum voluntary isometric contraction (MVIC) force and electromyography (EMG), drop jump (DJ) height and contact time at 1-min post-stretching. RESULTS: There were significant KE MVIC force impairments for both the SS (p = 0.006, d = 0.3, - 8.1%) and contralateral (p = 0.02, d = 0.20, - 4.2%) leg. With normalized data, there was a near-significant (p = 0.1), small magnitude (d = 0.29), greater force impairment with the ipsilateral (93.0 ± 12.8% of pre-test) versus the contralateral (96.2 ± 9.1% of pre-test) KE MVIC force. DJ height significantly improved for the stretched leg (p = 0.03, d = 0.18, + 9.2%) with near-significant, improvements for the contralateral leg (p = 0.06, d = 0.22, + 12.1%). For the stretched leg, DJ contact time was significantly (p = 0.04, d = 0.18, + 3.4%) prolonged, but there was no significant change with the contralateral leg. CONCLUSIONS: Unilateral hamstrings SS induced strength deficits in the ipsilateral and contralateral knee extension MVIC and a prolongation of the stretched leg DJ contact period. In anticipation of maximal force outputs, prolonged SS in isolation (no dynamic warm-up included) can have negative consequences on antagonist and contralateral muscle performance.


Assuntos
Músculos Isquiotibiais/fisiologia , Joelho/fisiologia , Força Muscular/fisiologia , Adulto , Feminino , Humanos , Contração Isométrica/fisiologia , Articulação do Joelho/fisiologia , Perna (Membro)/fisiologia , Masculino , Pessoa de Meia-Idade , Exercícios de Alongamento Muscular/métodos , Exercício de Aquecimento/fisiologia , Adulto Jovem
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