scholarly journals The specificity of explosive force production capacity quantified with the isometric rate of force development during leg extension in several sports athletes

2022 ◽  
Author(s):  
Kodayu ZUSHI ◽  
Yasushi KARIYAMA ◽  
Takuya YOSHIDA ◽  
Amane ZUSHI ◽  
Keigo OHYAMA-BYUN ◽  
...  
Keyword(s):  
Production Capacity ◽  
Force Production ◽  
Rate Of Force Development ◽  
Leg Extension ◽  
Force Development ◽  
Explosive Force

scholarly journals Assessment of Force Production in Parkinson’s Disease Subtypes

2021 ◽  
Vol 18 (19) ◽  
pp. 10044
Author(s):  
Paulo Henrique Silva Pelicioni ◽  
Marcelo Pinto Pereira ◽  
Juliana Lahr ◽  
Paulo Cezar Rocha dos Santos ◽  
Lilian Teresa Bucken Gobbi
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Force Production ◽  
Peak Force ◽  
Rate Of Force Development ◽  
Motor Symptom ◽  
Unsuccessful Attempt ◽  
Leg Extension ◽  
Force Development ◽  
Increased Risk

Muscle weakness is a secondary motor symptom of Parkinson’s disease (PD), especially in the subtype characterized by postural instability and gait difficulty (PIGD). Since the PIGD subtype also presents worse bradykinesia, we hypothesized that it also shows a decreased rate of force development, which is linked to an increased risk of falling in PD. Therefore, we investigated the effects of PD and PD subtypes on a force production profile and correlated the force production outcomes with clinical symptoms for each PD subtype. We assessed three groups of participants: 14 healthy older adults (OA), 10 people with PD composing the PIGD group, and 14 people with PD composing the tremor-dominant group. Three knee extension maximum voluntary isometric contractions were performed in a leg extension machine equipped with a load cell to assess the force production. The outcome measures were: peak force and rate of force development (RFD) at 50 ms (RFD50), 100 ms (RFD100), and 200 ms (RFD200). We observed lower peak force, RFD50, RFD100, and RFD200 in people with PD, regardless of subtypes, compared with the OA group (p < 0.05 for all comparisons). Together, our results indicated that PD affects the capacity to produce maximal and rapid force. Therefore, future interventions should consider rehabilitation programs for people with PD based on muscle power and fast-force production, and consequently reduce the likelihood of people with PD falling from balance-related events, such as from an unsuccessful attempt to avoid a tripping hazard or a poor and slower stepping response.

scholarly journals The Importance of Lean Body Mass for the Rate of Force Development in Taekwondo Athletes and Track and Field Throwers

2018 ◽  
Vol 3 (3) ◽  
pp. 43 ◽  
Author(s):  
Angeliki Kavvoura ◽  
Nikolaos Zaras ◽  
Angeliki-Nikoletta Stasinaki ◽  
Giannis Arnaoutis ◽  
Spyridon Methenitis ◽  
...  
Keyword(s):  
Lean Body Mass ◽  
Body Mass ◽  
Vastus Lateralis ◽  
Rate Of Force Development ◽  
Track And Field ◽  
Medial Gastrocnemius ◽  
Lower Body ◽  
Leg Extension ◽  
Force Development ◽  
The Relationship

The rate of force development (RFD) is vital for power athletes. Lean body mass (LBM) is considered to be an essential contributor to RFD, nevertheless high RFD may be achieved by athletes with either high or low LBM. The aim of the study was to describe the relationship between lower-body LBM and RFD, and to compare RFD in taekwondo athletes and track and field (T&F) throwers, the latter having higher LBM when compared to taekwondo athletes. Nine taekwondo athletes and nine T&F throwers were evaluated for countermovement jumping, isometric leg press and leg extension RFD, vastus lateralis (VL), and medial gastrocnemius muscle architecture and body composition. Lower body LBM was correlated with RFD 0–250 ms (r = 0.81, p = 0.016). Taekwondo athletes had lower LBM and jumping power per LBM. RFD was similar between groups at 30–50 ms, but higher for throwers at 80–250 ms. RFD adjusted for VL thickness was higher in taekwondo athletes at 30 ms, but higher in throwers at 200–250 ms. These results suggest that lower body LBM is correlated with RFD in power trained athletes. RFD adjusted for VL thickness might be more relevant to evaluate in power athletes with low LBM, while late RFD might be more relevant to evaluate in athletes with higher LBM.

The Optimal Joint Angle for Adductor Pollicis Force Production in Men and Women

1999 ◽  
Vol 24 (6) ◽  
pp. 570-580 ◽  
Author(s):  
David Ditor ◽  
Audrey Hicks
Keyword(s):  
Gender Difference ◽  
Key Words ◽  
Joint Angle ◽  
Force Production ◽  
Adductor Pollicis ◽  
Rate Of Force Development ◽  
Men And Women ◽  
Twitch Force ◽  
Force Development ◽  
Nondominant Hand

The purpose of this study was to determine the joint angle that allows for the greatest MVC and evoked twitch forces from the adductor pollicis (AP), and also whether there is a gender difference in either the above forces or the optimum thumb angle. Ten men (25.2 yrs) and 10 women (27.6 yrs) participated. The nondominant hand was placed palm-down with the thumb fixed at four angles of abduction (55, 70, 85, 100°). Male MVC forces were significantly greater than female, and there was no significant effect of joint angle on MVC force in either gender. For the evoked twitch, men were significantly stronger than women when tested at the 100 and 85° angles, and a significant effect was found for joint angle such that the lowest twitch force occurred at 55°. Men also tended to have a greater rate of force development than women (p = 0.07). These data suggest that studies using the AP muscle in stimulated and voluntary paradigms should use a thumb angle between 70 and 100° of abduction, or approximately 85°, and that the same angle can be used for both men and women. Key words: evoked twitch, MVC, gender, EMG, rate of force development

The differential effect of metabolic alkalosis on maximum force and rate of force development during repeated, high-intensity cycling

2013 ◽  
Vol 115 (11) ◽  
pp. 1634-1640 ◽  
Author(s):  
Jason C. Siegler ◽  
Paul W. M. Marshall ◽  
Sean Raftry ◽  
Cristy Brooks ◽  
Ben Dowswell ◽  
...  
Keyword(s):  
Sodium Bicarbonate ◽  
High Intensity ◽  
Differential Effect ◽  
Force Production ◽  
Rate Of Force Development ◽  
Maximum Force ◽  
Whole Body ◽  
Peak Power Output ◽  
Force Development ◽  
Maximal Force

The purpose of this investigation was to assess the influence of sodium bicarbonate supplementation on maximal force production, rate of force development (RFD), and muscle recruitment during repeated bouts of high-intensity cycling. Ten male and female ( n = 10) subjects completed two fixed-cadence, high-intensity cycling trials. Each trial consisted of a series of 30-s efforts at 120% peak power output (maximum graded test) that were interspersed with 30-s recovery periods until task failure. Prior to each trial, subjects consumed 0.3 g/kg sodium bicarbonate (ALK) or placebo (PLA). Maximal voluntary contractions were performed immediately after each 30-s effort. Maximal force (Fmax) was calculated as the greatest force recorded over a 25-ms period throughout the entire contraction duration while maximal RFD (RFDmax) was calculated as the greatest 10-ms average slope throughout that same contraction. Fmax declined similarly in both the ALK and PLA conditions, with baseline values (ALK: 1,226 ± 393 N; PLA: 1,222 ± 369 N) declining nearly 295 ± 54 N [95% confidence interval (CI) = 84–508 N; P < 0.006]. RFDmax also declined in both trials; however, a differential effect persisted between the ALK and PLA conditions. A main effect of condition was observed across the performance time period, with RFDmax on average higher during ALK (ALK: 8,729 ± 1,169 N/s; PLA: 7,691 ± 1,526 N/s; mean difference between conditions 1,038 ± 451 N/s, 95% CI = 17–2,059 N/s; P < 0.048). These results demonstrate a differential effect of alkalosis on maximum force vs. maximum rate of force development during a whole body fatiguing task.

The effect of rate of force development on maximal force production: acute and training-related aspects

2007 ◽  
Vol 99 (6) ◽  
pp. 605-613 ◽  
Author(s):  
Andreas Holtermann ◽  
Karin Roeleveld ◽  
Beatrix Vereijken ◽  
Gertjan Ettema
Keyword(s):  
Force Production ◽  
Rate Of Force Development ◽  
Force Development ◽  
Maximal Force ◽  
And Training

scholarly journals Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase

2015 ◽  
Vol 46 (1) ◽  
pp. 139-148 ◽  
Author(s):  
María Asunción Martínez-Valencia ◽  
Salvador Romero-Arenas ◽  
José L.L. Elvira ◽  
José María González-Ravé ◽  
Fernando Navarro-Valdivielso ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Training Stimulus ◽  
Force Production ◽  
Sprint Performance ◽  
Peak Force ◽  
Rate Of Force Development ◽  
Sprint Training ◽  
Force Output ◽  
Acceleration Phase ◽  
Force Development

AbstractResisted sprint training is believed to increase strength specific to sprinting. Therefore, the knowledge of force output in these tasks is essential. The aim of this study was to analyze the effect of sled towing (10%, 15% and 20% of body mass (Bm)) on sprint performance and force production during the acceleration phase. Twenty-three young experienced sprinters (17 men and 6 women; men = 17.9 ± 3.3 years, 1.79 ± 0.06 m and 69.4 ± 6.1 kg; women = 17.2 ± 1.7 years, 1.65 ± 0.04 m and 56.6 ± 2.3 kg) performed four 30 m sprints from a crouch start. Sprint times in 20 and 30 m sprint, peak force (Fpeak), a peak rate of force development (RFDpeak) and time to RFD (TRFD) in first step were recorded. Repeated-measures ANOVA showed significant increases (p ≤ 0.001) in sprint times (20 and 30 m sprint) for each resisted condition as compared to the unloaded condition. The RFDpeak increased significantly when a load increased (3129.4 ± 894.6 N·s−1, p ≤ 0.05 and 3892.4 ± 1377.9 N·s−1, p ≤ 0.01). Otherwise, no significant increases were found in Fpeak and TRFD. The RFD determines the force that can be generated in the early phase of muscle contraction, and it has been considered a factor that influences performance of force-velocity tasks. The use of a load up to 20% Bm might provide a training stimulus in young sprinters to improve the RFDpeak during the sprint start, and thus, early acceleration.

Maximal and explosive force production capacity and balance performance in men of different ages

1999 ◽  
Vol 79 (3) ◽  
pp. 260-267 ◽  
Author(s):  
M. Izquierdo ◽  
X. Aguado ◽  
R. Gonzalez ◽  
J. L. L�pez ◽  
K. H�kkinen
Keyword(s):  
Production Capacity ◽  
Force Production ◽  
Balance Performance ◽  
Different Ages ◽  
Explosive Force

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.

scholarly journals Lack of increased rate of force development after strength training is explained by specific neural, not muscular, motor unit adaptations

2021 ◽  
Author(s):  
Alessandro Del Vecchio ◽  
Andrea Casolo ◽  
Jakob Lund Dideriksen ◽  
Per Aagaard ◽  
Francesco Felici ◽  
...  
Keyword(s):  
Strength Training ◽  
Motor Unit ◽  
Discharge Rate ◽  
Force Production ◽  
Population Data ◽  
Motor Units ◽  
Rate Of Force Development ◽  
Force Development ◽  
Maximal Force ◽  
Contraction Speed

While maximal force increases following short-term isometric strength training, the rate of force development (RFD) may remain relatively unaffected. The underlying neural and muscular mechanisms during rapid contractions after strength training are largely unknown. Since strength training increases the neural drive to muscles, it may be hypothesized that there are distinct neural or muscular adaptations determining the change in RFD independently of an increase in maximal force. Therefore, we examined motor unit population data acquired from surface electromyography during the rapid generation of force before and after four weeks of strength training. We observed that strength training did not change the RFD because it did not influence the number of motor units recruited per second or their initial discharge rate during rapid contractions. While strength training did not change motoneuron behaviour in the force increase phase of rapid contractions, it increased the discharge rate of motoneurons (by ~4 spikes/s) when reaching the plateau phase (~150 ms) of the rapid contractions, determining an increase in maximal force production. Computer simulations with a motor unit model that included neural and muscular properties, closely matched the experimental observations and demonstrated that the lack of change in RFD following training is primarily mediated by an unchanged maximal recruitment speed of motoneurons. These results demonstrate that maximal force and contraction speed are determined by different adaptations in motoneuron behaviour following strength training and indicate that increases in the recruitment speed of motoneurons are required to evoke training-induced increases in RFD.

scholarly journals Quantification of Inter-Limb Symmetries With Rate of Force Development and Relaxation Scaling Factor

2021 ◽  
Vol 12 ◽  
Author(s):  
Darjan Smajla ◽  
Jure Žitnik ◽  
Nejc Šarabon
Keyword(s):  
Muscle Contraction ◽  
Outcome Measures ◽  
Force Production ◽  
Scaling Factor ◽  
Rate Of Force Development ◽  
Cross Sectional ◽  
Tennis Players ◽  
Force Development ◽  
Gender And Sports ◽  
Contraction And Relaxation

The inter-limb (a)symmetries have been most often assessed with the tests that quantify the maximal muscle capacity. However, the rapid force production and relaxation during submaximal tasks is equally important for successful sports performance. This can be evaluated with an established rate of force development and relaxation scaling factor (RFD-SF/RFR-SF). The aims of our study were (1) to assess the intra-session reliability of shortened RFD-SF/RFR-SF protocol and its absolute and symmetry outcome measures, (2) to compare the main absolute RFD-SF/RFR-SF outcome measures (slopes of RFD-SF and RFR-SF: kRTD–SF and kRFR–SF, theoretical peak RFD/RFR: TPRFD and TPRFR) across gender and sports groups, and (3) to compare inter-limb symmetries across gender and sports groups for main outcome measures (kRFD–SF, kRFR–SF, TPRFD, and TPRFR). A cross-sectional study was conducted on a group of young health participants (basketball and tennis players, and students): 30 in the reliability study and 248 in the comparison study. Our results showed good to excellent relative and excellent absolute reliability for the selected absolute and symmetry outcome measures (kRFD–SF, kRFR–SF, TPRFD, and TPRFR). We found significantly higher absolute values for kRFD–SF and TPRFD in males compared to females for the preferred (kRFD–SF: 9.1 ± 0.9 vs. 8.6 ± 0.9/s) and the non-preferred leg (kRFD–SF: 9.1 ± 0.9 vs. 8.5 ± 0.8/s), while there was no effect of sport. Significantly lower symmetry values for kRFR–SF (88.4 ± 8.6 vs. 90.4 ± 8.0%) and TPRFR (90.9 ± 6.8 vs. 92.5 ± 6.0%) were found in males compared to females. Moreover, tennis players had significantly higher symmetry values for kRFR–SF (91.1 ± 7.7%) and TPRFR (93.1 ± 6.0%) compared to basketball players (kRFR–SF: 88.4 ± 8.7% and TPRFR: 90.9 ± 6.7%) and students (kRFR–SF: 87.6 ± 8.7% and TPRFR: 90.5 ± 6.7%). Our results suggest that the reduced RFD-SF/RFR-SF protocol is a valuable and useful tool for inter-limb (a)symmetry evaluation. Differences in symmetry values in kRFR–SF and TPRFR (relaxation phase) were found between different sports groups. These may be explained by different mechanisms underlying the muscle contraction and relaxation. We suggest that muscle contraction and relaxation should be assessed for in-depth inter-limb symmetry investigation.

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