Impact of movement tempo on bar velocity and time under tension in resistance exercises with different external loads

2022 ◽  
Author(s):  
Robert Trybulski ◽  
Mariola Gepfert ◽  
Dawid Gawel ◽  
Marta Bichowska ◽  
Krzysztof Fostiak ◽  
...  
Keyword(s):  
Resistance Exercises ◽  
Bar Velocity ◽  
External Loads

scholarly journals How one feels during resistance exercises: A repetition by repetition analysis across exercises and loads

2019 ◽  
Author(s):  
Aviv Emanuel ◽  
Itzhak Rozen Smukas ◽  
Israel Halperin
Keyword(s):  
Resistance Training ◽  
Bench Press ◽  
Affective Valence ◽  
Trained Subjects ◽  
Task Failure ◽  
Position Transducer ◽  
Feeling Scale ◽  
Resistance Exercises ◽  
Bar Velocity

Purpose: The feeling scale (FS) is a unique and underexplored scale in sport sciences that measures affective valence. FS has the potential to be used in athletic environments as a monitoring and prescription tool. We sought to examine whether FS ratings, as measured on a repetition-by-repetition basis, can predict proximity to task-failure and bar velocity across different exercises and loads. Methods: On the first day, 20 trained subjects (10 females) completed 1RM tests in the barbell bench and squat exercises and were introduced to the FS. On the following three sessions, subjects completed three sets to task-failure with either 1) 70%1RM bench-press, 2) 70%1RM squat (squat-70%), or 3) 80%1RM squat (squat-80%). Sessions were completed in a randomized, counter-balanced order. After every completed repetition, subjects verbally reported their FS ratings. Bar velocity was measured via linear position transducer. Results: FS ratings predicted failure-proximity and bar velocity in all three conditions (p<0.001, R2 range: 0.66-0.85). Specifically, a reduction of one unit in the FS corresponded to approaching task-failure by 14%, 11% and 11%, and to a reduction in bar velocity of 10%, 4% and 3%, in the bench, squat-70% and squat-80%, respectively. Conclusion: This is the first study to investigate if the FS can be used in RT environments among trained subjects, on a repetition-by-repetition basis. The results show strong predictive abilities of the FS, indicating that the scale can be used to monitor and prescribe resistance training, and that its benefits should be further explored.

scholarly journals How One Feels During Resistance Exercises: A Repetition-by-Repetition Analysis Across Exercises and Loads

2021 ◽  
Vol 16 (1) ◽  
pp. 135-144 ◽  
Author(s):  
Aviv Emanuel ◽  
Isaac Rozen Smukas ◽  
Israel Halperin
Keyword(s):  
Resistance Training ◽  
Bench Press ◽  
Affective Valence ◽  
Repetition Maximum ◽  
Task Failure ◽  
Position Transducer ◽  
Feeling Scale ◽  
Resistance Exercises ◽  
Bar Velocity

Context: The Feeling Scale (FS) is a unique and underexplored scale in sport sciences that measures affective valence. The FS has the potential to be used in athletic environments as a monitoring and prescription tool. Purpose: To examine whether FS ratings, as measured on a repetition-by-repetition basis, can predict proximity to task failure and bar velocity across different exercises and loads. Methods: On the first day, 20 trained participants (10 females) completed 1-repetition-maximum (1-RM) tests in the barbell bench and squat exercises and were introduced to the FS. In the following 3 sessions, participants completed 3 sets to task failure with either (1) 70% 1-RM bench press, (2) 70% 1-RM squat (squat-70%), or (3) 80% 1-RM squat (squat-80%). Sessions were completed in a randomized, counterbalanced order. After every completed repetition, participants verbally reported their FS ratings. Bar velocity was measured via a linear position transducer. Results: FS ratings predicted failure proximity and bar velocity in all 3 conditions (P < .001, R2 .66–.85). Based on the analysis, which included over 2400 repetitions, a reduction of 1 unit in the FS corresponded to approaching task failure by 14%, 11%, and 11%, and to a reduction in bar velocity of 10%, 4%, and 3%, in the bench, squat-70%, and squat-80%, respectively. Conclusion: This is the first study to investigate whether the FS can be used in resistance-training environments among resistance-trained participants on a repetition-by-repetition basis. The results indicate that the FS can be used to monitor and prescribe resistance training and that its benefits should be further explored.

scholarly journals The Relationship Between the Lower-Body Muscular Profile and Swimming Start Performance

2016 ◽  
Vol 50 (1) ◽  
pp. 157-165 ◽  
Author(s):  
Amador García-Ramos ◽  
Katja Tomazin ◽  
Belén Feriche ◽  
Vojko Strojnik ◽  
Blanca de la Fuente ◽  
...  
Keyword(s):  
Peak Velocity ◽  
Correlation Coefficients ◽  
Dry Land ◽  
Leg Extension ◽  
Leg Flexion ◽  
Additional Resistance ◽  
Bar Velocity ◽  
The Relationship ◽  
External Loads ◽  
Squat Jumps

AbstractThis study aimed to examine the correlation of different dry land strength and power tests with swimming start performance. Twenty international level female swimmers (age 15.3 ± 1.6 years, FINA point score 709.6 ± 71.1) performed the track freestyle start. Additionally, dry land tests were conducted: a) squat (SJ) and countermovement jumps (CMJ), b) squat jumps with additional resistance equivalent to 25, 50, 75 and 100% of swimmers’ body weight [BW]), and c) leg extension and leg flexion maximal voluntary isometric contractions. Correlations between dry land tests and start times at 5, 10 and 15 m were quantified through Pearson’s linear correlation coefficients (r). The peak bar velocity reached during the jumps with additional resistance was the variable most correlated to swimming start performance (r = -0.57 to -0.66 at 25%BW; r = -0.57 to -0.72 at 50%BW; r = -0.59 to -0.68 at 75%BW; r = -0.50 to - 0.64 at 100%BW). A few significant correlations between the parameters of the SJ and the CMJ with times of 5 and 10 m were found, and none with the isometric variables. The peak velocity reached during jumps with external loads relative to BW was found a good indicator of swimming start performance.

Effects of combined acute versus chronic aerobic and resistance exercises on HbA1c, cardiovascular and immune functions in type 2 diabetic condition

2016 ◽  
Author(s):  
Sam Ibeneme ◽  
Obed Azubuike ◽  
Georgian Ibeneme ◽  
Ifeoma Okoye ◽  
Gerhard Fortwengel ◽  
...  
Keyword(s):  
Immune Functions ◽  
Resistance Exercises ◽  
Type 2 Diabetic

scholarly journals The Effects of External Loads and Muscle Forces on the Knee Joint Ligaments during Walking: A Musculoskeletal Model Study

2021 ◽  
Vol 11 (5) ◽  
pp. 2356
Author(s):  
Carlo Albino Frigo ◽  
Lucia Donno
Keyword(s):  
Knee Joint ◽  
Cruciate Ligament ◽  
Musculoskeletal Model ◽  
Optimization Approach ◽  
Muscle Forces ◽  
Collateral Ligaments ◽  
Flexion Extension ◽  
Lateral Collateral Ligaments ◽  
Gastrocnemius Muscles ◽  
External Loads

A musculoskeletal model was developed to analyze the tensions of the knee joint ligaments during walking and to understand how they change with changes in the muscle forces. The model included the femur, tibia, patella and all components of cruciate and collateral ligaments, quadriceps, hamstrings and gastrocnemius muscles. Inputs to the model were the muscle forces, estimated by a static optimization approach, the external loads (ground reaction forces and moments) and the knee flexion/extension movement corresponding to natural walking. The remaining rotational and translational movements were obtained as a result of the dynamic equilibrium of forces. The validation of the model was done by comparing our results with literature data. Several simulations were carried out by sequentially removing the forces of the different muscle groups. Deactivation of the quadriceps produced a decrease of tension in the anterior cruciate ligament (ACL) and an increase in the posterior cruciate ligament (PCL). By removing the hamstrings, the tension of ACL increased at the late swing phase, while the PCL force dropped to zero. Specific effects were observed also at the medial and lateral collateral ligaments. The removal of gastrocnemius muscles produced an increase of tension only on PCL and lateral collateral ligaments. These results demonstrate how musculoskeletal models can contribute to knowledge about complex biomechanical systems as the knee joint.

scholarly journals Understanding Covalent Grafting of Nanotubes onto Polymer Nanocomposites: Molecular Dynamics Simulation Study

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2621
Author(s):  
Seunghwa Yang
Keyword(s):  
Molecular Dynamics ◽  
Load Transfer ◽  
Cell Model ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Covalent Grafting ◽  
Modelling Strategies ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
External Loads

Here, we systematically interrogate the effects of grafting single-walled (SWNT) and multi-walled carbon nanotubes (MWNT) to polymer matrices by using molecular dynamics (MD) simulations. We specifically investigate key material properties that include interfacial load transfer, alteration of nanotube properties, and dispersion of nanotubes in the polymer matrix. Simulations are conducted on a periodic unit cell model of the nanocomposite with a straight carbon nanotube and an amorphous polyethylene terephthalate (PET) matrix. For each type of nanotube, either 0%, 1.55%, or 3.1% of the carbon atoms in the outermost nanotubes are covalently grafted onto the carbon atoms of the PET matrix. Stress-strain curves and the elastic moduli of nanotubes and nanocomposites are determined based on the density of covalent grafting. Covalent grafting promotes two rivalling effects with respect to altering nanotube properties, and improvements in interfacial load transfer in the nanocomposites are clearly observed. The enhanced interface enables external loads applied to the nanocomposites to be efficiently transferred to the grafted nanotubes. Covalent functionalization of the nanotube surface with PET molecules can alter the solubility of nanotubes and improve dispersibility. Finally, we discuss the current limitations and challenges in using molecular modelling strategies to accurately predict properties on the nanotube and polymers systems studied here.

scholarly journals Associations between Well-Being State and Match External and Internal Load in Amateur Referees

2021 ◽  
Vol 18 (6) ◽  
pp. 3322
Author(s):  
Eñaut Ozaeta ◽  
Javier Yanci ◽  
Carlo Castagna ◽  
Estibaliz Romaratezabala ◽  
Daniel Castillo
Keyword(s):  
External Load ◽  
Contact Time ◽  
Well Being ◽  
Ground Contact ◽  
Internal Load ◽  
Match Play ◽  
Power Meter ◽  
Ground Contact Time ◽  
Training Impulse ◽  
External Loads

The main aim of this paper was to examine the association between prematch well-being status with match internal and external load in field (FR) and assistant (AR) soccer referees. Twenty-three FR and 46 AR participated in this study. The well-being state was assessed using the Hooper Scale and the match external and internal loads were monitored with Stryd Power Meter and heart monitors. While no significant differences were found in Hooper indices between match officials, FR registered higher external loads (p < 0.01; ES: 0.75 to 5.78), spent more time in zone 4 and zone 5, and recorded a greater training impulse (TRIMP) value (p < 0.01; ES: 1.35 to 1.62) than AR. Generally, no associations were found between the well-being variables and external loads for FR and AR. Additionally, no associations were found between the Hooper indices and internal loads for FR and AR. However, several relationships with different magnitudes were found between internal and external match loads, for FR, between power and speed with time spent in zone 2 (p < 0.05; r = −0.43), ground contact time with zone 2 and zone 3 (p < 0.05; r = 0.50 to 0.60) and power, speed, cadence and ground contact time correlated with time spent in zone 5 and TRIMP (p < 0.05 to 0.01; r = 0.42 to 0.64). Additionally, for AR, a relationship between speed and time in zone 1 was found (p < 0.05; r = −0.30; CL = 0.22). These results suggest that initial well-being state is not related to match officials’ performances during match play. In addition, the Stryd Power Meter can be a useful device to calculate the external load on soccer match officials.

scholarly journals Electromechanical Response of Smart Ultra-High Performance Concrete under External Loads Corresponding to Different Electrical Measurements

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1281
Author(s):  
Min Kyoung Kim ◽  
Huy Viet Le ◽  
Dong Joo Kim
Keyword(s):  
Electrical Resistivity ◽  
High Performance ◽  
High Performance Concrete ◽  
Steel Slag ◽  
Measurement Methods ◽  
Electrical Measurements ◽  
Ultra High Performance Concrete ◽  
Ac Measurement ◽  
External Loads ◽  
Functional Fillers

This study investigated the electromechanical response of smart ultra-high-performance concretes (smart UHPCs), containing fine steel slag aggregates (FSSAs) and steel fibers as functional fillers, under external loads corresponding to different measurement methods. Regardless of different measurement methods of electrical resistance, the smart UHPCs under compression showed a clear reduction in their electrical resistivity. However, under tension, their electrical resistivity measured from direct current (DC) measurement decreased, whereas that from alternating current (AC) measurement increased. This was because the electrical resistivity, from DC measurement, of smart UHPCs was primarily dependent on fiber crack bridging, whereas that from AC measurement was dependent on tunneling effects.

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