scholarly journals Effects of Different Inter-Set Rest Intervals during the Nordic Hamstring Exercise in Young Male Athletes

2021 ◽  
Author(s):  
Benjamin Drury ◽  
Daniel Peacock ◽  
Jason Moran ◽  
Chris Cone ◽  
Rodrigo Ramirez-Campillo
Keyword(s):  
Resistance Training ◽  
Force Production ◽  
Young Male ◽  
Team Sport ◽  
Peak Force ◽  
Average Force ◽  
Male Athletes ◽  
Main Effects ◽  
Percent Decline ◽  
Rest Intervals

Abstract Context The Nordic hamstring exercise (NHE) is known to reduce hamstrings injury (HIS) risk in athletes. In order to optimise the NHE it is important to understand how acute resistance training variables influence its performance. Objective To examine the effects of different inter-set rest intervals (ISRI) on force indices during performance of the NHE. Design: Crossover Study. Setting Laboratory based. Patients or Participants Ten (age = 20.7 ± 2.3 years; height = 179.4 ± 5.5 cm; body mass = 83.9 ± 12.4 kg) well-trained young male team-sport athletes. Intervention Participants performed 2 x 6 repetitions of the NHE with either a SHORT (one-minute) or LONG (three-minute) ISRI. All sets were performed on the NordBord. Main Outcomes Measure(s) Peak force (N), average force (N), percent maintenance (%) and percent decline (%) were recorded for both dominant and non-dominant limbs as well as inter-limb force asymmetries (%) calculated. Results Analyses revealed no statistically significant interactions or main effects (p > 0.05) between conditions and sets in all variables. However, analysis of individual repetitions showed significant reductions (p < 0.05, ES = 0.58–1.28) in peak force from repetition four onwards. Conclusions Our findings suggest that a one-minute ISRI is sufficient to maintain force production qualities and inter-limb asymmetries between sets during the NHE in well-trained athletes. However, practitioners should be aware of the potentially high decrements in peak force production that may occur within the set.

scholarly journals Implementing a Circadian Adaptation Schedule after Eastward Flight in Young Male Athletes

2021 ◽  
Vol 11 (21) ◽  
pp. 9962
Author(s):  
Dean J. Miller ◽  
Gregory D. Roach ◽  
Michele Lastella ◽  
Aaron T. Scanlan ◽  
Charli Sargent
Keyword(s):  
Light Exposure ◽  
Core Body Temperature ◽  
Intervention Group ◽  
Young Male ◽  
Control Group ◽  
Jet Lag ◽  
Time Zone ◽  
Male Athletes ◽  
Main Effects ◽  
Core Body

This study examined the effectiveness of a circadian adaptation schedule in male cricketers after an 8.5 h eastward time zone change. Ten participants (aged 18.7 ± 0.9 y) were randomly assigned to a control group or an intervention group. Participants in the intervention group followed a light exposure schedule in which they were instructed to seek light in the three hours preceding, and avoid light in the three hours following their estimated core body temperature minimum. The rate of adaptation was assessed using the nightly excretion rate of urinary 6-sulphatoxymelatonin (aMT6s). General linear mixed models were conducted to assess the effect of condition (i.e., control and light intervention) on nocturnal secretion of aMT6s. Significant main effects of day (F(7, 35) = 10.4, p < 0.001) were reflected by an increase in nocturnal melatonin excretion (i.e., all participants gradually adapted to the destination time zone). Subjective jet lag decreased by day (F(7, 54) = 22.9, p < 0.001), bedtime was delayed by day (F(7, 54) = 3.1, p = 0.007) and get up time was earlier by day (F(7, 35) = 5.4, p < 0.001). On average, it took 7 days for all participants to return to baseline levels following transmeridian travel. Similarly, it took 7 days for subjective jet lag to alleviate. In the initial 4 days of the protocol, the intervention group registered higher levels of nocturnal urinary melatonin, however, there was no significant differences in the rate of adaptation between the groups. It is possible that participants did not adhere to the intervention or that they followed the intervention but it was ineffective.

scholarly journals Suspended lunge exercise: assessment of forces in different positions and paces

2019 ◽  
Vol 37 (1) ◽  
pp. 57-64
Author(s):  
Joan Aguilera-Castells ◽  
Bernat Buscà Safont-Tria ◽  
Javier Peña López ◽  
Azahara Fort-Vanmeerhaeghe ◽  
Mònica Solana-Tramunt ◽  
...  
Keyword(s):  
Body Position ◽  
Force Production ◽  
Repeated Measurements ◽  
Peak Force ◽  
Upper Body ◽  
Average Force ◽  
Physically Active ◽  
Dynamic Contraction ◽  
Contraction Type ◽  
Male University Students

The forces exerted on the suspension device have been examined in upper body exercises, like push-ups or inverted raw. For this reason, this aim of this study was to determine the effect of body position, contraction patterns and pace on force production by the lower limb during the execution of suspended lunge exercises. Ten physically active male university students (n = 10, age = 23.70±2.83 years old) performed sixteen suspended lunges in four different positions and three different paces (60, 70, and 80 beats per minute). A load cell was used to assess the forces exert on the suspension device. Force data were analyzed with the factorial repeated measurements (ANOVA). A significant main effect for position in concentric force (p= .000), average force (p= .002), and for frequency in peak force (p= .004) were found. Peak force was significantly higher for dynamic contraction type in all positions in comparison with isometric suspended lunge. In conclusion, a higher feet distance, frequencies around 70 beats per minute and the dynamic contraction type enhanced the forces exert on the suspension strap when performed the lunge exercise.

scholarly journals ‘Everything is said with a smile’: Homonegative speech acts in sport

2020 ◽  
pp. 101269022095752
Author(s):  
Froukje Smits ◽  
Annelies Knoppers ◽  
Agnes Elling-Machartzki
Keyword(s):  
Speech Acts ◽  
Young Male ◽  
Team Sport ◽  
Cultural Norms ◽  
Male Athletes ◽  
Gay Males ◽  
Young Males ◽  
Western Countries ◽  
Heterosexual Male ◽  
And Gender

The acceptance of gay males in sport is growing in various western countries. However, research also suggests that young males, including athletes, tend to engage in homonegative speech acts, often called microaggressions, that make it difficult for them to navigate practices of masculinity. We used solicited diaries or diary logs written by (non-)heterosexual young male team sport athletes (aged 16–25) to investigate how they experienced and heard expressions of homonegative and heteronormative microaggressive speech acts. We drew on Foucault’s notion of discourse, Butler’s conceptualization of performativity of heteronormativity and Sue’s work on microaggressions to examine how microaggressive speech acts by young male athletes reflect current sexual and gender cultural norms. The results revealed how homonegative speech acts were embedded in a gay aesthetic and abject femininity and used to endorse a desirable heteronormative masculinity. We concluded that homonegative microaggressive speech acts contribute to the preservation of discursive heteronormativity in sport despite growing acceptance of non-heterosexual male athletes.

scholarly journals Sled-Pull Load–Velocity Profiling and Implications for Sprint Training Prescription in Young Male Athletes

Sports ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 119 ◽  
Author(s):  
Micheál J. Cahill ◽  
Jon L. Oliver ◽  
John B. Cronin ◽  
Kenneth P. Clark ◽  
Matt R. Cross ◽  
...  
Keyword(s):  
High School ◽  
Confidence Intervals ◽  
Young Male ◽  
Team Sport ◽  
Maximal Velocity ◽  
Sprint Training ◽  
Young Athletes ◽  
Male Athletes ◽  
Velocity Relationship ◽  
School Team

The purpose of this study was to examine the usefulness of individual load–velocity profiles and the between-athlete variation using the decrement in maximal velocity (Vdec) approach to prescribe training loads in resisted sled pulling in young athletes. Seventy high school, team sport, male athletes (age 16.7 ± 0.8 years) were recruited for the study. All participants performed one un-resisted and four resisted sled-pull sprints with incremental resistance of 20% BM. Maximal velocity was measured with a radar gun during each sprint and the load–velocity relationship established for each participant. A subset of 15 participants was used to examine the reliability of sled pulling on three separate occasions. For all individual participants, the load–velocity relationship was highly linear (r > 0.95). The slope of the load–velocity relationship was found to be reliable (coefficient of variation (CV) = 3.1%), with the loads that caused a decrement in velocity of 10, 25, 50, and 75% also found to be reliable (CVs = <5%). However, there was a large between-participant variation (95% confidence intervals (CIs)) in the load that caused a given Vdec, with loads of 14–21% body mass (% BM) causing a Vdec of 10%, 36–53% BM causing a Vdec of 25%, 71–107% BM causing a Vdec of 50%, and 107–160% BM causing a Vdec of 75%. The Vdec method can be reliably used to prescribe sled-pulling loads in young athletes, but practitioners should be aware that the load required to cause a given Vdec is highly individualized.

Divergent Performance Outcomes Following Resistance Training Using Repetition Maximums or Relative Intensity

2019 ◽  
Vol 14 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Kevin M. Carroll ◽  
Jake R. Bernards ◽  
Caleb D. Bazyler ◽  
Christopher B. Taber ◽  
Charles A. Stuart ◽  
...  
Keyword(s):  
Resistance Training ◽  
Relative Intensity ◽  
Effect Size ◽  
Vertical Jump ◽  
Force Production ◽  
Performance Outcomes ◽  
Peak Force ◽  
Rate Of Force Development ◽  
Effect Sizes ◽  
Force Development

Purpose: To compare repetition maximum (RM) to relative intensity using sets and repetitions (RISR) resistance training on measures of training load, vertical jump, and force production in well-trained lifters. Methods: Fifteen well-trained (isometric peak force = 4403.61 [664.69] N, mean [SD]) males underwent resistance training 3 d/wk for 10 wk in either an RM group (n = 8) or RISR group (n = 7). Weeks 8 to 10 consisted of a tapering period for both groups. The RM group achieved a relative maximum each day, whereas the RISR group trained based on percentages. Testing at 5 time points included unweighted (<1 kg) and 20-kg squat jumps, countermovement jumps, and isometric midthigh pulls. Mixed-design analyses of variance and effect size using Hedge’s g were used to assess within- and between-groups alterations. Results: Moderate between-groups effect sizes were observed for all squat-jump and countermovement-jump conditions supporting the RISR group (g = 0.76–1.07). A small between-groups effect size supported RISR for allometrically scaled isometric peak force (g = 0.20). Large and moderate between-groups effect sizes supported RISR for rate of force development from 0 to 50 ms (g = 1.25) and 0 to 100 ms (g = 0.89). Weekly volume load displacement was not different between groups (P > .05); however, training strain was statistically greater in the RM group (P < .05). Conclusions: Overall, this study demonstrated that RISR training yielded greater improvements in vertical jump, rate of force development, and maximal strength compared with RM training, which may be explained partly by differences in the imposed training stress and the use of failure/nonfailure training in a well-trained population.

Neuromuscular drive and force production are not altered during bilateral contractions

1998 ◽  
Vol 84 (1) ◽  
pp. 200-206 ◽  
Author(s):  
J. M. Jakobi ◽  
E. Cafarelli
Keyword(s):  
Motor Unit ◽  
Force Production ◽  
Young Male ◽  
Neuromuscular Control ◽  
Force Generation ◽  
Isometric Contractions ◽  
Firing Rates ◽  
Significant Limitation ◽  
Motor Unit Firing ◽  
Male Subjects

Jakobi, J. M., and E. Cafarelli. Neuromuscular drive and force production are not altered during bilateral contractions. J. Appl. Physiol. 84(1): 200–206, 1998.—Several investigators have studied the deficit in maximal voluntary force that is said to occur when bilateral muscle groups contract simultaneously. A true bilateral deficit (BLD) would suggest a significant limitation of neuromuscular control; however, some of the data from studies in the literature are equivocal. Our purpose was to determine whether there is a BLD in the knee extensors of untrained young male subjects during isometric contractions and whether this deficit is associated with a decreased activation of the quadriceps, increased activation of the antagonist muscle, or an alteration in motor unit firing rates. Twenty subjects performed unilateral (UL) and bilateral (BL) isometric knee extensions at 25, 50, 75, and 100% maximal voluntary contraction. Total UL and BL force (Δ3%) and maximal rate of force generation (Δ2.5%) were not significantly different. Total UL and BL maximal vastus lateralis electromyographic activity (EMG; 2.7 ± 0.28 vs. 2.6 ± 0.24 mV) and coactivation (0.17 ± 0.02 vs. 0.20 ± 0.02 mV) were also not different. Similarly, the ratio of force to EMG during submaximal UL and BL contractions was not different. Analysis of force production by each leg in UL and BL conditions showed no differences in force, rate of force generation, EMG, motor unit firing rates, and coactivation. Finally, assessment of quadriceps activity with the twitch interpolation technique indicated no differences in the degree of voluntary muscle activation (UL: 93.6 ± 2.51 Hz, BL: 90.1 ± 2.43 Hz). These results provide no evidence of a significant limitation in neuromuscular control between BL and UL isometric contractions of the knee extensor muscles in young male subjects.

The effects of pH on force and stiffness development in mouse muscles

1987 ◽  
Vol 65 (8) ◽  
pp. 1798-1801 ◽  
Author(s):  
J. M. Renaud ◽  
R. B. Stein ◽  
T. Gordon
Keyword(s):  
High Frequency ◽  
Small Amplitude ◽  
Force Production ◽  
Muscle Length ◽  
Low Ph ◽  
Muscle Stiffness ◽  
Average Force ◽  
Cross Bridge ◽  
Effects Of Ph ◽  
Cross Bridges

Changes in force and stiffness during contractions of mouse extensor digitorum longus and soleus muscles were measured over a range of extracellular pH from 6.4 to 7.4. Muscle stiffness was measured using small amplitude (<0.1% of muscle length), high frequency (1.5 kHz) oscillations in length. Twitch force was not significantly affected by changes in pH, but the peak force during repetitive stimulation (2, 3, and 20 pulses) was decreased significantly as the pH was reduced. Changes in muscle stiffness with pH were in the same direction, but smaller in extent. If the number of attached cross-bridges in the muscle can be determined from the measurement of small amplitude, high frequency muscle stiffness, then these findings suggest that (a) the number of cross-bridges between thick and thin filaments declines in low pH and (b) the average force per cross-bridge also declines in low pH. The decline in force per cross-bridge could arise from a reduction in the ability of cross-bridges to generate force during their state of active force production and (or) in an increased percentage of bonds in a low force, "rigor" state.

scholarly journals The acute caffeine ingestion improved performance during traditional and cluster‐based resistance training models in resistance‐trained male athletes

2021 ◽  
Vol 35 (S1) ◽  
Author(s):  
Majid Koozehchian ◽  
Amir Sarshin ◽  
Zahra Hatami Nasab ◽  
Alireza Naderi ◽  
Alireza Rahimi ◽  
...  
Keyword(s):  
Resistance Training ◽  
Caffeine Ingestion ◽  
Male Athletes ◽  
Training Models ◽  
Improved Performance
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