Impulse-Based Dynamic Strength Index

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Michael H. Haischer ◽  
John Krzyszkowski ◽  
Stuart Roche ◽  
Kristof Kipp
Keyword(s):  
Dynamic Strength ◽  
Strength Index

Interrelationship between specific high-intensity intermittent efforts ability with aerobic capacity and slow stretch-shortening cycle utilization in taekwondo athletes

2021 ◽  
pp. 1-10
Author(s):  
Alex Ojeda-Aravena ◽  
Tomás Herrera-Valenzuela ◽  
Pablo Valdés-Badilla ◽  
Eduardo Baez-San Martín ◽  
José Zapata-Bastías ◽  
...  
Keyword(s):  
Aerobic Capacity ◽  
High Intensity ◽  
Dynamic Strength ◽  
Multiple Regression Model ◽  
Strength Index ◽  
Male Athletes ◽  
Squat Jump ◽  
Stretch Shortening Cycle ◽  
The Relationship ◽  
Shuttle Run

BACKGROUND: Repeat high-intensity intermittent efforts is a taekwondo-specific ability but the influence of aerobic capacity and dynamic strength characteristics on this ability has received relatively little attention in the literature. OBJECTIVE: To examine the relationship between specific high-intensity intermittent efforts with aerobic capacity and slow stretch-shortening cycle utilization in taekwondo athletes. METHODS: Nineteen taekwondo male athletes were assessed by squat jump (SJ), countermovement jump (CMJ), 20-meter shuttle run (20MSR), and frequency speed of kick test multiple (FSKTMULT). From the FSKTMULT, total kicks and kick decrement index [KDI] were calculated. Additionally, from both jump tests, the slow stretch-shortening cycle utilization (Slow SSC Utilization) was determined from the eccentric utilization ratio [EUR], pre-stretch augmentation [PSA], and reactive strength index [RSI]. RESULTS: There were positive and significant correlations between total kicks with 20MSR (r= 0.85; p= 0.00) and SJ (r= 0.66; p< 0.05). The multiple regression model demonstrated that total kicks where significantly influenced by 20MSR (R2= 71%; p= 0.00). Additionally, only EUR and RSI explained total kicks performance to a greater proportion (R2= 76%). CONCLUSIONS: The FSKTMULT total kicks performance is positively correlated and influenced by aerobic capacity and slow SSC utilization.

Reliability of the Dynamic Strength Index in College Athletes

2015 ◽  
Vol 10 (5) ◽  
pp. 542-545 ◽  
Author(s):  
Christopher Thomas ◽  
Paul A. Jones ◽  
Paul Comfort
Keyword(s):  
College Athletes ◽  
Intraclass Correlation ◽  
Force Production ◽  
Dynamic Strength ◽  
Peak Force ◽  
Dynamic Force ◽  
Strength Index ◽  
Training Interventions ◽  
Change In The Mean ◽  
Change In Mean

Purpose:To determine the reliability of the Dynamic Strength Index (DSI) in college athletes.Method:Nineteen male college athletes performed the squat jump (SJ) and isometric midthigh pull (IMTP) to determine peak force, on 2 separate days. Reliability was assessed by intraclass correlation coefficient (ICC), typical error (TE), percentage change in the mean, smallest worthwhile change (SWC), and coefficient of variation (%CV).Results:Peak force for the SJ was 2137 ± 499 N and 2781 ± 435 N for the IMTP, resulting in a mean DSI of 0.78 ± 0.19. Peak forces in the SJ (ICC = .99, TE = 57.22 N, change in mean = 0.2%, SWC = 4.7%, CV = 2.6%) and IMTP (ICC = .95, TE = 104.22 N, change in mean = 0.5%, SWC = 3.1%, CV = 3.8%) were considered highly reliable between sessions. However, IMTP peak force was the only variable with an overall TE < SWC. The DSI was also highly reliable (ICC = .97, TE = 0.03, change in mean = −0.3%, SWC = 5.1%, CV = 4.6%) between sessions.Conclusion:This study demonstrates that peak force in the SJ and IMTP are reliable, resulting in a reliable assessment of dynamic-force-production capabilities via the DSI. The DSI may be used to guide individualized training interventions and monitor specific adaptations to training. Changes in SJ peak force, IMTP peak force, and DSI were >4.67%, 3.13%, and 5.13%, respectively, identifying meaningful changes in response to training or competition.

scholarly journals Changes in Dynamic Strength Index in Response to Strength Training

Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 176 ◽  
Author(s):  
Paul Comfort ◽  
Christopher Thomas ◽  
Thomas Dos’Santos ◽  
Timothy Suchomel ◽  
Paul Jones ◽  
...  
Keyword(s):  
Strength Training ◽  
Collegiate Athletes ◽  
Dynamic Strength ◽  
Minimal Change ◽  
Peak Force ◽  
Effect Sizes ◽  
Strength Index ◽  
Countermovement Jump ◽  
Strength Based ◽  
Moderate Difference

The primary aim of this investigation was to determine the effects of a four-week period of in-season strength training on the dynamic strength index (DSI). Pre and post a four-week period of strength-based training, twenty-four collegiate athletes (age = 19.9 ± 1.3 years; height = 1.70 ± 0.11 m; weight 68.1 ± 11.8 kg) performed three isometric mid-thigh pulls and countermovement jumps to permit the calculation of DSI. T-tests and Cohen’s effect sizes revealed a significant but small (p = 0.009, d = 0.50) decrease in DSI post-training (0.71 ± 0.13 N·N−1) compared to pre-training (0.65 ± 0.11 N·N−1); however, when divided into high and low DSI groups, differential responses were clear. The low DSI group exhibited no significant or meaningful (p = 1.000, d = 0.00) change in DSI pre to post-training (0.56 ± 0.05 N·N−1, 0.56 ± 0.09 N·N−1, respectively), whereas the high DSI group demonstrated a significant and large decrease (p = 0.034, d = 1.29) in DSI pre to post-training (0.85 ± 0.05 N·N−1, 0.74 ± 0.11 N·N−1, respectively), resulting in a significant and moderate difference (p = 0.034, d = 1.29) in the change in DSI between groups. These results demonstrate that DSI decreases in response to strength training, as expected, due to an increase in isometric mid-thigh pull peak force, with minimal change in dynamic (countermovement jump) peak force.

scholarly journals A Comparison of Dynamic Strength Index between Team-Sport Athletes

Sports ◽  
2017 ◽  
Vol 5 (3) ◽  
pp. 71 ◽  
Author(s):  
Christopher Thomas ◽  
Thomas Dos’Santos ◽  
Paul Jones
Keyword(s):  
Dynamic Strength ◽  
Team Sport ◽  
Strength Index

scholarly journals RELIABILITY AND MINIMAL DETECTABLE CHANGES OF BENCH PRESS, BACK SQUAT, REACTIVE AND DYNAMIC STRENGTH INDEX

2021 ◽  
Vol 53 (8S) ◽  
pp. 49-49
Author(s):  
Jad Adrian Washif ◽  
Kim Hebert-Losier ◽  
Nicholas Gill ◽  
Mazwan Zainuddin ◽  
Nur Sulastri Nasruddin ◽  
...  
Keyword(s):  
Bench Press ◽  
Dynamic Strength ◽  
Strength Index ◽  
Back Squat

scholarly journals Dynamic Strength Index: Relationships with Common Performance Variables and Contextualization of Training Recommendations

2020 ◽  
Vol 74 (1) ◽  
pp. 59-70
Author(s):  
Timothy J. Suchomel ◽  
Christopher J. Sole ◽  
Christopher R. Bellon ◽  
Michael H. Stone
Keyword(s):  
Peak Power ◽  
Female Athletes ◽  
Training Stimulus ◽  
Monitoring Program ◽  
Collegiate Athletes ◽  
Dynamic Strength ◽  
Peak Force ◽  
Power Performance ◽  
Strength Index

Abstract The purposes of this study were to examine the relationships between dynamic strength index (DSI) and other strength-power performance characteristics and to contextualize DSI scores using case study comparisons. 88 male and 67 female NCAA division I collegiate athletes performed countermovement jumps (CMJ) and isometric mid-thigh pulls (IMTP) during a pre-season testing session as part of a long-term athlete monitoring program. Spearman’s correlations were used to assess the relationships between DSI and CMJ peak force, height, modified reactive strength index, peak power and IMTP peak force and rate of force development (RFD). Very large relationships existed between DSI and IMTP peak force (r = -0.848 and -0.746), while small-moderate relationships existed between DSI and CMJ peak force (r = 0.297 and 0.313), height (r = 0.108 and 0.167), modified reactive strength index (r = 0.174 and 0.274), and IMTP RFD (r = -0.341 and -0.338) for men and women, respectively. Finally, relationships between DSI and CMJ peak power were trivial-small for male (r = 0.008) and female athletes (r = 0.191). Case study analyses revealed that despite similar DSI scores, each athlete’s percentile rankings for each variable and CMJ force-time characteristics were unique, which may suggest different training emphases are needed. Based on the explained variance, an athlete’s IMTP performance may have a larger influence on their DSI score compared to the CMJ. DSI scores should be contextualized using additional performance data to ensure each individual athlete receives the appropriate training stimulus during different training phases throughout the year.

scholarly journals Comparison of Methods of Calculating Dynamic Strength Index

2018 ◽  
Vol 13 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Paul Comfort ◽  
Christopher Thomas ◽  
Thomas Dos’Santos ◽  
Paul A. Jones ◽  
Timothy J. Suchomel ◽  
...  
Keyword(s):  
Intraclass Correlation ◽  
Dynamic Strength ◽  
Rugby League ◽  
Strength Index ◽  
Countermovement Jump ◽  
Reliable Measure ◽  
Male Youth ◽  
Squat Jump ◽  
Youth Soccer ◽  
Very High

Purpose: To determine the reliability and variability of the Dynamic Strength Index (DSI) calculated from squat-jump (SJ) vs countermovement-jump (CMJ) peak force (PF) and to compare DSI values between methods. Methods: Male youth soccer and rugby league players (N = 27; age 17.2 ± 0.7 y, height 173.9 ± 5.7 cm, body mass 71.1 ± 7.2 kg) performed 3 trials of the SJ, CMJ, and isometric midthigh pull (IMTP) on 2 separate days. DSI was calculated by dividing the PF during each jump by the IMTP PF. Results: DSI-SJ exhibited moderate (intraclass correlation coefficient [ICC] = .419) within-session reliability and high variability (percentage coefficient of variation [%CV] = 15.91) during session 1; however, this improved noticeably during session 2 (ICC = .948, %CV = 4.03). In contrast, DSI-CMJ showed nearly perfect within-session reliability (ICC = .920–.952) and low variability (%CV = 3.80–4.57) for both sessions. Moreover, DSI-SJ values demonstrated a small yet significant increase between sessions (P = .01, d = 0.37), whereas only a trivial and nonsignificant increase was observed for DSI-CMJ between sessions (P = .796, d = 0.07). Between-sessions reliability was very high for the DSI-SJ (ICC = .741) and nearly perfect for the DSI-CMJ (ICC = .924). There was no significant or meaningful difference (P = .261, d = 0.12) between DSI-SJ (0.82 ± 0.18) and DSI-CMJ (0.84 ± 0.15). Conclusions: Practitioners should use DSI-CMJ, as it is a more reliable measure than DSI-SJ, although it produces similar ratios.

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