The Post-Activation Potentiation Effect on Squat Jump Performance: Age and Sex Effect

2014 ◽  
Vol 26 (2) ◽  
pp. 187-194 ◽  
Author(s):  
Fotini Arabatzi ◽  
Dimitrios Patikas ◽  
Andreas Zafeiridis ◽  
Konstantinos Giavroudis ◽  
Theodoros Kannas ◽  
...  
Keyword(s):  
Pediatric Population ◽  
Reaction Force ◽  
Conditioning Stimulus ◽  
Vertical Ground Reaction Force ◽  
Jump Performance ◽  
Squat Jump ◽  
Potentiation Effect ◽  
Males And Females ◽  
And Control ◽  
Age And Sex

This study examined the post-activation potentiation (PAP) effects on squat jump (SJ) performance and on peak rate of force development (RFDpeak) in preadolescent (10–12 y), adolescents (14–15 y) and adults (20–25 y) males and females. All participants performed a SJ with and without prior conditioning stimulus (PAP and control protocol, respectively), consisting of 3 × 3-second maximal isometric squats. Jump height and RFDpeak of the vertical ground reaction force during SJ were assessed before, and at 20 seconds and at 4 minutes following the conditioning stimulus. The results revealed a different pattern of age-effect on SJ performance within males and females. The RFDpeak significantly increased as a factor of age in both males and females (P < .05). Increase in SJ performance after conditioning stimulus occurred only in men (P < .05), with no effects in teen-males, boys, and female groups. There was a significant PAP effect on RFDpeak in both adult groups (P < .05) and teen-males, with no effects in children. In conclusion, the PAP effects on SJ performance and RFDpeak are age- and sex-dependent; that is PAP appears as a viable method for acutely enhancing SJ performance in men but not in pediatric population.

scholarly journals Neuromuscular taping application in counter movement jump: biomechanical insight in a group of healthy basketball players

2017 ◽  
Vol 27 (2) ◽  
Author(s):  
Giuseppe Marcolin ◽  
Alessandro Buriani ◽  
Andrea Giacomelli ◽  
David Blow ◽  
Davide Grigoletto ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Functional Performance ◽  
Reaction Force ◽  
Lower Limbs ◽  
Healthy Male ◽  
Vertical Ground Reaction Force ◽  
Basketball Players ◽  
Jump Performance ◽  
Combined Application ◽  
Negative Effect

Kinesiologic elastic tape is widely used for both clinical and sport applications although its efficacy in enhancing agonistic performance is still controversial. Aim of the study was to verify in a group of healthy basketball players whether a neuromuscular taping application (NMT) on ankle and knee joints could affect the kinematic and the kinetic parameters of the jump, either by enhancing or inhibiting the functional performance. Fourteen healthy male basketball players without any ongoing pathologies at upper limbs, lower limbs and trunk volunteered in the study. They randomly performed 2 sets of 5 counter movement jumps (CMJ) with and without application of Kinesiologic tape. The best 3 jumps of each set were considered for the analysis. The Kinematics parameters analyzed were: knees maximal flexion and ankles maximal dorsiflexion during the push off phase, jump height and take off velocity. Vertical ground reaction force and maximal power expressed in the push off phase of the jump were also investigated. The NMT application in both knees and ankles showed no statistically significant differences in the kinematic and kinetic parameters and did not interfere with the CMJ performance. Bilateral NMT application in the group of healthy male basketball players did not change kinematics and kinetics jump parameters, thus suggesting that its routine use should have no negative effect on functional performance. Similarly, the combined application of the tape on both knees and ankles did not affect in either way jump performance.

Enhanced Performance With Elastic Resistance During the Eccentric Phase of a Countermovement Jump

2013 ◽  
Vol 8 (2) ◽  
pp. 181-187 ◽  
Author(s):  
Saied Jalal Aboodarda ◽  
Ashril Yusof ◽  
N.A. Abu Osman ◽  
Martin W. Thompson ◽  
A. Halim Mokhtar
Keyword(s):  
Power Output ◽  
High Speed ◽  
Tensile Force ◽  
Reaction Force ◽  
Jump Height ◽  
Vertical Ground Reaction Force ◽  
Jump Performance ◽  
Leg Stiffness ◽  
Significant Difference ◽  
Infrared Cameras

Purpose:To identify the effect of additional elastic force on the kinetic and kinematic characteristics, as well as the magnitude of leg stiffness, during the performance of accentuated countermovement jumps (CMJs).Methods:Fifteen trained male subjects performed 3 types of CMJ including free CMJ (FCMJ; ie, body weight), ACMJ-20, and ACMJ-30 (ie, accentuated eccentric CMJ with downward tensile force equivalent to 20% and 30% body mass, respectively). A force platform synchronized with 6 high-speed infrared cameras was used to measure vertical ground-reaction force (VGRF) and displacement.Results:Using downward tensile force during the lowering phase of a CMJ and releasing the bands at the start of the concentric phase increased maximal concentric VGRF (6.34%), power output (23.21%), net impulse (16.65%), and jump height (9.52%) in ACMJ-30 compared with FCMJ (all P < .05). However, no significant difference was observed in the magnitude of leg stiffness between the 3 modes of jump. The results indicate that using downward recoil force of the elastic material during the eccentric phase of a CMJ could be an effective method to enhance jump performance by applying a greater eccentric loading on the parallel and series elastic components coupled with the release of stored elastic energy.Conclusions:The importance of this finding is related to the proposition that power output, net impulse, takeoff velocity, and jump height are the key parameters for successful athletic performance, and any training method that improves impulse and power production may improve sports performance, particularly in jumping aspects of sport.

Muscle performance during maximal isometric and dynamic contractions is influenced by the stiffness of the tendinous structures

2005 ◽  
Vol 99 (3) ◽  
pp. 986-994 ◽  
Author(s):  
Jens Bojsen-Møller ◽  
S. Peter Magnusson ◽  
Lars Raundahl Rasmussen ◽  
Michael Kjaer ◽  
Per Aagaard
Keyword(s):  
Mechanical Properties ◽  
Vastus Lateralis ◽  
Reaction Force ◽  
Muscle Performance ◽  
Jump Height ◽  
Force Transmission ◽  
Vertical Ground Reaction Force ◽  
Jump Performance ◽  
Muscle Actions ◽  
Squat Jumps

Contractile force is transmitted to the skeleton through tendons and aponeuroses, and, although it is appreciated that the mechanocharacteristics of these tissues play an important role for movement performance with respect to energy storage, the association between tendon mechanical properties and the contractile muscle output during high-force movement tasks remains elusive. The purpose of the study was to investigate the relation between the mechanical properties of the connective tissue and muscle performance in maximal isometric and dynamic muscle actions. Sixteen trained men participated in the study. The mechanical properties of the vastus lateralis tendon-aponeurosis complex were assessed by ultrasonography. Maximal isometric knee extensor force and rate of torque development (RTD) were determined. Dynamic performance was assessed by maximal squat jumps and countermovement jumps on a force plate. From the vertical ground reaction force, maximal jump height, jump power, and force-/velocity-related determinants of jump performance were obtained. RTD was positively related to the stiffness of the tendinous structures ( r = 0.55, P < 0.05), indicating that tendon mechanical properties may account for up to 30% of the variance in RTD. A correlation was observed between stiffness and maximal jump height in squat jumps and countermovement jumps ( r = 0.64, P < 0.05 and r = 0.55, P < 0.05). Power, force, and velocity parameters obtained during the jumps were significantly correlated to tendon stiffness. These data indicate that muscle output in high-force isometric and dynamic muscle actions is positively related to the stiffness of the tendinous structures, possibly by means of a more effective force transmission from the contractile elements to the bone.

scholarly journals Isokinetic Strength, Vertical Jump Performance, and Strength Differences in First Line Professional Firefighters Competing in Fire Sport

2021 ◽  
Vol 18 (7) ◽  
pp. 3448
Author(s):  
Petr Miratsky ◽  
Tomas Gryc ◽  
Lee Cabell ◽  
Frantisek Zahalka ◽  
Matej Brozka ◽  
...  
Keyword(s):  
Vertical Jump ◽  
Reaction Force ◽  
Knee Extensors ◽  
Isokinetic Strength ◽  
Strength Ratio ◽  
First Line ◽  
Vertical Ground Reaction Force ◽  
Jump Performance ◽  
Isokinetic Testing ◽  
In Fire

The purpose of our study was to investigate peak torque (PT) of knee extensors (KE) and knee flexors (KF), bilateral and unilateral strength asymmetries in isokinetic testing and vertical jump height (JH), vertical ground reaction force (VGRF), and force differences (ΔVGRF) between legs during different jump tests in professional first-line firefighters (n = 15) competing in fire sports disciplines. There was a significant effect of jump type on JH (F2,44 = 7.23, p < 0.05), VGRF (F2,44 = 16.03, p < 0.05), and ΔVGRF (F2,44 = 3.45, p < 0.05). Professional firefighters achieved a mean JH of 50.17 cm in the countermovement jump free arms and high PT of KEs (3.15 Nm/kg). No significant differences (p > 0.05) and small effect sizes (d < 0.3) were found between the legs when PTs were assessed. We found a slightly higher (d = 0.53) unilateral strength ratio in non-dominant legs (58.12 ± 10.26%) compared to dominant legs (55.31 ± 7.51%). No effect of laterality was found among limb comparisons, but a higher unilateral isokinetic strength ratio was found in non-dominant legs of firefighters. A high level of strength (PT of KEs > 3 times body weight) and vertical jump performance is comparable to the performance of elite athletic populations.

scholarly journals Effects of a Low-Load Gluteal Warm-Up on Explosive Jump Performance

2015 ◽  
Vol 46 (1) ◽  
pp. 177-187 ◽  
Author(s):  
Thomas Comyns ◽  
Ian Kenny ◽  
Gerard Scales
Keyword(s):  
Repeated Measures ◽  
Reaction Force ◽  
Force Production ◽  
Peak Power Output ◽  
Future Research ◽  
Jump Performance ◽  
Squat Jump ◽  
Warm Up ◽  
Low Load ◽  
Squat Jumps

AbstractThe purpose of this study was to investigate the effects of a low-load gluteal warm-up protocol on countermovement and squat jump performance. Research by Crow et al. (2012) found that a low-load gluteal warm-up could be effective in enhancing peak power output during a countermovement jump. Eleven subjects performed countermovement and squat jumps before and after the gluteal warm-up protocol. Both jumps were examined in separate testing sessions and performed 30 seconds, and 2, 4, 6 & 8 minutes post warm-up. Height jumped and peak ground reaction force were the dependent variables examined in both jumps, with 6 additional variables related to fast force production being examined in the squat jump only. All jumps were performed on a force platform (AMTI OR6-5). Repeated measures analysis of variance found a number of significant differences (p ≤ 0.05) between baseline and post warm-up scores. Height jumped decreased significantly in both jumps at all rest intervals excluding 8 minutes. Improvement was seen in 7 of the 8 recorded SJ variables at the 8 minute interval. Five of these improvements were deemed statistically significant, namely time to peak GRF (43.0%), and time to the maximum rate of force development (65.7%) significantly decreased, while starting strength (63.4%), change of force in first 100 ms of contraction (49.1%) and speed strength (43.6%) significantly increased. The results indicate that a gluteal warm-up can enhance force production in squat jumps performed after 8 minutes recovery. Future research in this area should include additional warm-up intervention groups for comparative reasons.

scholarly journals Single- versus multi-joint isometric protocols to induce a post activation potentiation effect on squat jump performance

2020 ◽  
Vol 21 (3) ◽  
pp. 71-80 ◽  
Author(s):  
Thyago Garcia ◽  
Juliano Pupo ◽  
Débora Knihs ◽  
Osvaldo Furlaneto Rodrigues ◽  
Haiko Zimmermann ◽  
...  
Keyword(s):  
Jump Performance ◽  
Squat Jump ◽  
Potentiation Effect ◽  
Single Versus

scholarly journals Effect of an Arm Swing on Countermovement Vertical Jump Performance in Elite Volleyball Players

2016 ◽  
Vol 53 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Frantisek Vaverka ◽  
Daniel Jandačka ◽  
David Zahradník ◽  
Jaroslav Uchytil ◽  
Roman Farana ◽  
...  
Keyword(s):  
Body Position ◽  
Vertical Jump ◽  
Reaction Force ◽  
The Body ◽  
Jump Height ◽  
Vertical Ground Reaction Force ◽  
Average Force ◽  
Jump Performance ◽  
Arm Swing ◽  
Volleyball Players

AbstractThe aim of this study was to determine how elite volleyball players employed the arm swing (AS) to enhance their jump performance. The study assessed how the AS influenced the duration and magnitude of the vertical ground reaction force (VGRF) during the main phases (preparatory, braking and accelerating) of the countermovement vertical jump (CMVJ), the starting position of the body at the beginning of the accelerating phase and the moment when the AS began contributing to increasing the jump height. Eighteen elite volleyball players performed three CMVJs with and without an AS. Kinetics and kinematics data were collected using two Kistler force plates and the C-motion system. The time and force variables were evaluated based on the VGRF, and the position of the body and the trajectory of the arm movement were determined using kinematic analysis. The AS improved the CMVJ by increasing the jump height by 38% relative to jumping without an AS. The AS significantly shortened the braking phase and prolonged the accelerating phase, however, it did not influence the preparatory phase or the overall jump duration. The AS also significantly increased the average force during the accelerating phase as well as the accelerating impulse. The AS upward began at 76% into the overall jump duration. The AS did not influence the body position at the beginning of the accelerating phase. These findings can be used to improve performance of the CMVJ with the AS and in teaching beginning volleyball players proper jumping technique.

Mantle Of The Expert Strategy Effectiveness In The Development Of Creative Thinking

2019 ◽  
Author(s):  
Ibrahim Arman
Keyword(s):  
Creative Thinking ◽  
Role Playing ◽  
Thinking Skills ◽  
Measurement Unit ◽  
Quasi Experimental ◽  
Males And Females ◽  
The Mean ◽  
Girls School ◽  
And Control ◽  
Experimental Group

<p>This study aimed at investigating the Effectiveness of Mantle of the Expert in creative thinking Skills among the 7<sup>th</sup> Graders. The study conducted on a sample of 7<sup>th</sup> Graders at Kober Secondary Boys School and Upper Kober Elementary Girls School. The study sample consisted of (100) students split into two groups (experimental and control). The researcher adopting the Torrance test for creative thinking the verbal image "A" by examining the tests used in the Ristow study (1988), Edwards and Baldov (1987) study, and designing a teacher book for the (engineering and measurement) unit according to the integration between the strategies of the mantle of the expert and role playing.</p> <p>This study adopted quasi-experimental design. It included two groups (experimental and controlled) in two branches (males and females) for each group. The controlled group was taught by using the traditional method whereas the experimental group by the mantle of the expert. The data analyzed using (ANCOVA) test to measure the differences in the development of creative thinking between the control and experimental groups.</p> <p>The Conclusions showed that there are statistically significant differences in the mean scores of the creative thinking test due to the way, gender and interaction between them.</p> <p>Based on the Conclusions of the study, the researcher recommends the need to use the mantles of the expert in the teaching of mathematics.</p>

scholarly journals Running ground reaction forces across footwear conditions are predicted from the motion of two body mass components

2019 ◽  
Vol 126 (5) ◽  
pp. 1315-1325 ◽  
Author(s):  
Andrew B. Udofa ◽  
Kenneth P. Clark ◽  
Laurence J. Ryan ◽  
Peter G. Weyand
Keyword(s):  
Ground Reaction Force ◽  
Lower Limb ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Vertical Ground Reaction Force ◽  
Time Patterns ◽  
Foot Strike ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Force Time

Although running shoes alter foot-ground reaction forces, particularly during impact, how they do so is incompletely understood. Here, we hypothesized that footwear effects on running ground reaction force-time patterns can be accurately predicted from the motion of two components of the body’s mass (mb): the contacting lower-limb (m1 = 0.08mb) and the remainder (m2 = 0.92mb). Simultaneous motion and vertical ground reaction force-time data were acquired at 1,000 Hz from eight uninstructed subjects running on a force-instrumented treadmill at 4.0 and 7.0 m/s under four footwear conditions: barefoot, minimal sole, thin sole, and thick sole. Vertical ground reaction force-time patterns were generated from the two-mass model using body mass and footfall-specific measures of contact time, aerial time, and lower-limb impact deceleration. Model force-time patterns generated using the empirical inputs acquired for each footfall matched the measured patterns closely across the four footwear conditions at both protocol speeds ( r2 = 0.96 ± 0.004; root mean squared error  = 0.17 ± 0.01 body-weight units; n = 275 total footfalls). Foot landing angles (θF) were inversely related to footwear thickness; more positive or plantar-flexed landing angles coincided with longer-impact durations and force-time patterns lacking distinct rising-edge force peaks. Our results support three conclusions: 1) running ground reaction force-time patterns across footwear conditions can be accurately predicted using our two-mass, two-impulse model, 2) impact forces, regardless of foot strike mechanics, can be accurately quantified from lower-limb motion and a fixed anatomical mass (0.08mb), and 3) runners maintain similar loading rates (ΔFvertical/Δtime) across footwear conditions by altering foot strike angle to regulate the duration of impact. NEW & NOTEWORTHY Here, we validate a two-mass, two-impulse model of running vertical ground reaction forces across four footwear thickness conditions (barefoot, minimal, thin, thick). Our model allows the impact portion of the impulse to be extracted from measured total ground reaction force-time patterns using motion data from the ankle. The gait adjustments observed across footwear conditions revealed that runners maintained similar loading rates across footwear conditions by altering foot strike angles to regulate the duration of impact.

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