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 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 Standard reference values of the upper body posture in healthy middle-aged female adults in Germany

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniela Ohlendorf ◽  
Polyna Sosnov ◽  
Julia Keller ◽  
Eileen M. Wanke ◽  
Gerhard Oremek ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Standing Position ◽  
Repeated Measurements ◽  
Clinical Diagnostics ◽  
Body Posture ◽  
Upper Body ◽  
Back Surface ◽  
Left Shoulder ◽  
Upper Body Posture ◽  
Standard Values

AbstractIn order to classify and analyze the parameters of upper body posture, a baseline in form of standard values is demanded. To this date, standard values have only been published for healthy young women. Data for female adults between 51 and 60 years are lacking. 101 symptom-free female volunteers aged 51–60 (55.16 ± 2.89) years. The mean height of the volunteers was 1.66 ± 0.62 m, with a mean body weight of 69.3 ± 11.88 kg and an average BMI of 25.02 ± 4.55 kg/m2. By means of video raster stereography, a 3D-scan of the upper back surface was measured in a habitual standing position. The confidence interval, tolerance range and ICCs were calculated for all parameters. The habitual standing position is almost symmetrical in the frontal plane the most prominent deviation being a slightly more ventral position of the left shoulder blade in comparison to the right. The upper body (spine position) is inclined ventrally with a minor tilt to the left. In the sagittal plane, the kyphosis angle of the thoracic spine is greater than the lordosis angle of the lumbar spine. The pelvis is virtually evenly balanced with deviations from an ideal position falling under the measurement error margin of 1 mm/1°. There were also BMI influenced postural variations in the sagittal plane and shoulder distance. The ICCs are calculated from three repeated measurements and all parameters can be classified as "almost perfect". Deflections from an ideally symmetric spinal alignment in women aged 51–60 years are small-scaled, with a minimal frontal-left inclination and accentuated sigmoidal shape of the spine. Postural parameters presented in this survey allow for comparisons with other studies as well as the evaluation of clinical diagnostics and applications.

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 Force Production during the Sustained Phase of Rugby Scrums: A Systematic Literature Review

2020 ◽  
Author(s):  
Eric Martin ◽  
George Beckham
Keyword(s):  
Literature Review ◽  
Systematic Literature Review ◽  
Statistical Power ◽  
Assessment Tool ◽  
Body Position ◽  
Body Height ◽  
Force Production ◽  
Cross Sectional ◽  
Testing Procedures ◽  
Rugby Players

Abstract Background: Since World Rugby changed the laws regarding scrums in the 2013-2014 season, the sustained push phase of the scrum has increased in tactical importance. Therefore, the purpose of this systematic literature review was to examine the biomechanical demands during the sustained push phase of individual, unit, and full pack scrummaging. Methods: Pubmed, EBSCO (specifically and simultaneously searching Academic Search Premier, CINAHL, and SPORTDiscus), and Google Scholar were searched for any research that presented force production in a live or simulated rugby scrum. Study quality was appraised using the National Institute of Health's Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Recorded scrum forces, positioning of players including joint angles, and testing procedures were extracted and narratively synthesized. Results: Twenty six studies were included in the review. 50% of included studies were rated good, 31% fair, and 19% poor. Major limitations included not reporting any effect size, statistical power, or reliability. Reported group mean values for average sustained forces against a machine generally ranged from 1000-2000 N in individual scrums and 4000-8000 N for full packs of male rugby players older than high school age. Individuals seem to optimize their force generation when their shoulders are set against scrum machine pads at approximately 40% of body height, with feet parallel, and with knee and hip angles around 120°. A 10% difference in pack force seems to be necessary for one pack to drive another back in the scrum, but little data exist to quantify differences in force production between winning and losing packs during live scrums. Data collection within studies was not standardized, making comparisons difficult. There is a lack of data in live scrums, and the current research indicates that machine scrums may not replicate many of the demands of live scrums. There is a lack of data for female rugby players. Conclusions: This review indicates an optimal individual body position for players to strive to achieve during scrummaging, consisting of a low body height (40% of stature) and large extended hip and knee angles (120° each).

scholarly journals Effects of Different Forms of Extrinsic Feedback on the Accuracy of Force Production and to Differentiate this Force in the Simple Cyclic Movements of the Upper and Lower Limb

2020 ◽  
Vol 72 (3) ◽  
pp. 39-56
Author(s):  
Stefan Szczepan ◽  
Zofia Wróblewska ◽  
Andrzej Klarowicz ◽  
Ryszard Błacha ◽  
Marek Rejman
Keyword(s):  
Lower Limb ◽  
Retention Test ◽  
Repeated Measures ◽  
Body Height ◽  
Force Production ◽  
Lower Limbs ◽  
Verbal Feedback ◽  
Physically Active ◽  
Cyclic Movements ◽  
Extrinsic Feedback

Abstract Background: This study aimed to assess the accuracy of force production by the limbs and to identify the ability to differentiate this force during a progressively increasing value, in response to different types of extrinsic feedback. Material and methods: The study involved nineteen healthy and physically active boys and girls aged 12.82±0.34 years, body height 157.05±9.02 cm, and body mass 44.89±7.89 kg. The tasks were to perform a series of right and left upper limb pulls and pushes with increasing force using the levers of the kinesthesiometer and a series of lower limb presses on the pedal of the kinesthesiometer. The tasks were completed in three feedback conditions: no feedback, sound feedback, verbal feedback, and the retention test was used. To assess the level of accuracy of force production, the novel index of force production accuracy (FPAIndex) was used. Results: The outcomes expressing the value of FPAIndex on the point scale indicated that the highest level of kinesthetic differentiation was observed when no feedback was provided (1.17 points), and the lowest kinesthetic differentiation was recorded when verbal feedback was provided (3.33 points). However, they were devoid of statistical value. The repeated-measures analysis of variance ANOVA with the Tukey post-hoc test (HSD) indicated a significant lowest (p=0.0402) level of accuracy of FPA (x̄ 36.12±18.29 [N]) only for the act of left lower limb press (LL PRESS) in the retention test, while no feedback was provided to the subjects. Conclusions: The results of this study showed that verbal and sound extrinsic feedback did not affect the accuracy of force production by the upper and lower limbs and the ability to differentiate this force in simple movements among children.

Effect of Body Position on Force Production During the Isometric Midthigh Pull

2018 ◽  
Vol 32 (1) ◽  
pp. 48-56 ◽  
Author(s):  
George K. Beckham ◽  
Kimitake Sato ◽  
Hugo A.P. Santana ◽  
Satoshi Mizuguchi ◽  
G. Gregory Haff ◽  
...  
Keyword(s):  
Body Position ◽  
Force Production

Acute beetroot juice administration improves peak isometric force production in adolescent males

2018 ◽  
Vol 43 (8) ◽  
pp. 816-821 ◽  
Author(s):  
David Bender ◽  
Jeremy R. Townsend ◽  
William C. Vantrease ◽  
Autumn C. Marshall ◽  
Ruth N. Henry ◽  
...  
Keyword(s):  
Isometric Force ◽  
Force Production ◽  
Sprint Performance ◽  
Peak Force ◽  
Adolescent Males ◽  
Height Velocity ◽  
Beetroot Juice ◽  
Repeated Sprint ◽  
Group Time ◽  
Isometric Force Production

The purpose of this study was to examine the effects of acute beetroot juice (BR) administration on repeated sprint performance and isometric force production in adolescent males. Twelve male adolescents (age, 16.8 ± 1.0 years; height, 178.8 ± 9.2 cm; mass, 74.8 ± 12.5 kg; peak height velocity, 2.53 ± 1.2 years) participated in this double-blind, placebo-controlled, crossover designed study. Participants consumed 2 × 70 mL of BR (∼12.9 mmol NO3−; Beet It Sport) or a nitrate-depleted placebo (PL) at 2.5 h prior to performing isometric mid-thigh pulls (IMTP) and 4 repeated 20-s Wingate sprints interspersed with 4 min of rest. Sprint data were analyzed by a 2 × 4 (group × time) repeated-measures ANOVA while a dependent t test was used to compare conditions for IMTP peak force. A significant main effect for time (p < 0.05) was observed for peak power (PP), average power (Pavg), and fatigue index (FI) across sprints. Compared with sprint 1, sprint 4 resulted in significant decreases in PP (p < 0.000; −16.6%) and Pavg (p = 0.000; −21.8%) and FI was significantly elevated (p < 0.000; 15.2%). No significant group × time interactions were observed between conditions for PP (p = 0.402), Pavg (p = 0.479), or FI (p = 0.37). IMTP peak force was significantly higher (p = 0.004; 13.9%) following BR consumption compared with PL. The repeated sprint protocol resulted in significant fatigue while BR did not influence sprint performance. However, it appears BR administration may improve peak force production in adolescent males.

Effect of Load, Angle, and Contraction Type on Clinically Assessed Knee Joint Position Sense

2021 ◽  
pp. 1-6
Author(s):  
Adam L. Haggerty ◽  
Janet E. Simon ◽  
Dustin R. Grooms ◽  
Jeffrey A. Russell
Keyword(s):  
Body Position ◽  
Eccentric Contraction ◽  
Position Sense ◽  
Joint Position Sense ◽  
Joint Position ◽  
Active Joint ◽  
Concentric Contraction ◽  
Target Angle ◽  
Significant Difference ◽  
Contraction Type

Context: Proprioception is an individual’s awareness of body position in 3-dimensional space. How proprioceptive acuity changes under varying conditions such as joint position, load, and concentric or eccentric contraction type is not well understood. In addition, a limitation of the variety of techniques to assess proprioception is the lack of clinically feasible methods to capture proprioceptive acuity. The purpose of this study was to implement a readily available instrument, a smartphone, in the clinical evaluation of knee active joint position sense and to determine how joint angle, joint loading, and quadriceps contraction type affect an individual’s active joint position sense. Design: Cross-over study. Methods: Twenty healthy, physically active university participants (10 women and 10 men: 21.4 [2.0] y; 1.73 [0.1] m; 70.9 [14.3] kg) were recruited. Individuals were included if they had no neurological disorder, no prior knee surgery, and no recent knee injury. The participants were given a verbal instruction to locate a target angle and then were tasked with reproducing the target angle without visual or verbal cues. An accelerometer application on a smartphone was used to assess the angle to the nearest tenth of a degree. Three variables, each with 2 levels, were analyzed in this study: load (weighted and unweighted), contraction type (eccentric and concentric), and joint position (20° and 70°). A repeated-measures analysis of variance was conducted to assess the within-subjects factors of load, contraction, and position. Results: A significant difference of 0.50° (0.19°) of greater error with eccentric versus concentric contraction (P = .02) type was identified. In addition, a significant interaction was found for contraction × position, with a mean increase in error of 0.98° (0.33°) at the 20° position when contracting eccentrically (P = .03). Conclusions: Contraction type, specifically eccentric contraction at 20°, showed significantly greater error than concentric contraction. This suggests that, during eccentric contractions of the quadriceps, there may be decreased proprioceptive sensitivity compared with concentric contractions.

scholarly journals Kinetic Analysis of Water Fitness Exercises: Contributions for Strength Development

2019 ◽  
Vol 16 (19) ◽  
pp. 3784 ◽  
Author(s):  
Santos ◽  
Rama ◽  
Marinho ◽  
Barbosa ◽  
Costa
Keyword(s):  
Upper Limb ◽  
Force Production ◽  
Peak Force ◽  
Strength Development ◽  
Isokinetic Dynamometer ◽  
Symmetric Motion ◽  
Pressure System ◽  
Dry Land ◽  
Force Variation ◽  
Selection Of

The evaluation of propulsive forces in water allows the selection of the most appropriate strategies to develop strength during water fitness sessions. The aim of this study was threefold: (i) to analyze the rate of force production; (ii) to analyze the rate of force variation; and (iii) to compare limbs’ symmetry in two water fitness exercises. Twenty-two young health subjects (age: 21.23 ± 1.51 years old, body mass: 67.04 ± 9.31 kg, and height: 166.36 ± 8.01 cm) performed incremental protocols of horizontal adduction (HA) and rocking horse (RHadd), from 105 until 150 b·min–1. Data acquisition required an isokinetic dynamometer and a differential pressure system that allowed the assessment of (a) isometric peak force of dominant upper limb (IsometricFD); (b) propulsive peak force of dominant upper limb (PropulsiveFD); and (c) propulsive peak force of nondominant upper limb (PropulsiveFND). Significant differences were found in the rate of force production (RateFD) between the majority cadences in both exercises. The RateFD reached ~68% of the force in dry-land conditions, and lower cadences promoted a higher rate of force variation (ΔForce). Most actions were asymmetric, except for the HA at 135 b·min–1. In conclusion, the musical cadence of 135 b·min–1 seems to elicit a desired rate of force production with a symmetric motion in both exercises.

scholarly journals Peak Rate of Force Development and Isometric Maximum Strength of Back Muscles Are Associated With Power Performance During Load-Lifting Tasks

2019 ◽  
Vol 13 (1) ◽  
pp. 155798831982862 ◽  
Author(s):  
Erika Zemková ◽  
Oliver Poór ◽  
Juraj Pecho
Keyword(s):  
Peak Force ◽  
Rate Of Force Development ◽  
Power Performance ◽  
Mean Power ◽  
Back Muscles ◽  
Maximal Voluntary Isometric Contraction ◽  
Physically Active ◽  
Mean Values ◽  
Force Development ◽  
Lifting Task

This study investigates the relationship between peak force and rate of force development (RFD) obtained from maximal voluntary isometric contraction (MVC) of the back muscles and the power produced during a loaded lifting task. A group of 27 resistance-trained and 41 recreationally physically active men performed a maximal isometric strength test of the back muscles and a deadlift to high pull while lifting progressively increasing weights. Peak RFD correlated significantly with the peak and mean power produced during a deadlift to high pull with lower weights (from 20 to 40 kg), with r values ranging from .941 to .673 and from .922 to .633. The r2 values ranged from .89 to .45 and from .85 to .40, explaining 89%–45% and 85%–40% of total variance. There were also significant relationships between MVC peak force and peak and mean values of power produced during a deadlift to high pull with weights ≥60 kg ( r in range from .764 to .888 and from .735 to .896). Based on r2, a moderate-to-high proportion of variance was explained (58%–79% and 54%–80%). These findings indicate that peak RFD obtained from MVC of the back muscles may be predictive of power performance during a lifting task at light loads. In addition to MVC peak force produced by back muscles, the ability of subjects to develop a high force in a short time should be evaluated in order to gain deeper insight into a loaded lifting performance, namely, in those prone to low back pain.

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