PresentationPDF Available

Optimal load for maximizing power during sled sprinting - ECSS 2016 Presentation

Authors:

Abstract and Figures

Optimal load for maximizing power during sled sprinting
No caption available
… 
No caption available
… 
No caption available
… 
No caption available
… 
Content may be subject to copyright.
OPTIMAL LOAD PROFILING FOR
MAXIMIZING POWER IN SLED
RESISTED SPRINTING
Matt R. Cross, MSpEx
Matt Brughelli, PhD
Pierre Samozino, PhD
Jean-Benoît Morin, PhD
Improving acceleration
How do we effectively train sprint acceleration?
Horizontal POWER = Key
Physical + Technical (e.g. Morin & Rabita 2016)
Optimized increase = unknown
Resisted'sprints
‘The'Big'3
UL'sprints
Eccentrics
?
! " # $ %
Resisted sprinting
Specific horizontal overload stimulus
Common + easy to implement (e.g. sleds)
Basis for loading prescription
‘Optimal’ = max load without kinematic disruption
(i.e. <12.6% BM or ~10% vDec) (Alcaraz 2006; Lockie 2010)
‘Heavier= better acc. stimulus? (Petrakos 2016)
No current kinetic basis for
resisted sprint prescription
OPTIMIZING'HORIZONTAL'POWER
‘Optimal profiling’ for power
= Determining kinetic conditions
which maximize power
(e.g. Sargeant 1984; Linosier 1996)
Assess using multiple trials
Jumps/sprints with load
Find optimal conditions + training load
Use load to train & maximize power
Previous research & studies
Cycling, jumping, treadmill sprinting
No research for over-ground sprinting
Requires practical training tool
RESEARCH QUESTIONS
1. Can FvP relationships be
profiled using multiple sled
sprints?
2. What is the optimal load that
maximizes power?
3.
?
Soccer
Football
vs.
& " # $ %
# " ' $ ( ) #
*+,- ) #
.
Assessment of power at vmax
assumed zero
Furusawa 1927
/0$ #
1
234 5 ) /0467 5
€90
Equipment
Common sled + harness
Radar for assessing vmax
Procedures
Recreational (N=12) +
Sprinters (N=15)
6-7 sprints, 5 min rest
Progressive loading:
0-120% of BM
+20% BM increments until
>50% decrement in UL vmax
Variable distance: 20-45 m
Data analysis
888888888889:;<
=>" #
*+,- ) #.
&>" %?*@ $ #A
Individual composite
relationships compiled
Fv = Least square linear
Pv = 2nd order polynomial
#B, %B8C8!
?*@ calculated
=DEF, 9DEF8C8G-HI
Statistical processes
MBIs: ES±90% CIs, likelihood
Reliability: ICC, CV% + standardized change (ES)
Calculated for each
trial & plotted
Results
The method WORKS
FvP relationships well fitted with linear &
poly. regressions
Good test-retest reliability (ICC=0.73-0.97;
CV=1.0-5.4%, trivial-small)
R20.977
P<0.001
!"#$%&'()*
à
&')"+*,)&
%B(m·s-1
)
8.35
±0.38 17% v. large***
9.75
±
0.36
#B(N·kg-1
)
6.6 ±0.5 9% moderate** 7.3 ±0.7
!
?*@ (W·kg-1
)
13.8 ±1.5 27% v. large*** 17.4 ±1.8
#-HI (N·kg-1
)
3.4 ±0.3 7% moderate*3.6 ±0.4
%-HI (m·s-1
)
4.19
±0.19 17% V. l arg e***
4.90
±
0.18
G-HI
(kg)
64 ±11 -1% 64 ± 7
G-HI
%BM
78 ± 6 5% small* 82 ± 8
*likely; **very likely; ***extremely likely
Lopt ='46-82'kg
-./.-0%12%3!444
-.5.60 785.-0
Summary
Optimal loading for max
power can be profiled with
sleds
Loads appear individualized and greater
magnitudes than used in the literature
>69% vs. <42.6% BM
our findings current research*
Practical applications
If aiming to ↑'horizontal power
heavyloads may provide greater stimulus
NOTE: Technique not considered
àLongitudinal effects of training
need to be assessed
FRICTION IS KEY vs. vs.
…So'what…?
Training using optimal load
Test on each training surface
Build to vmax
HOLD for extended period
e.g. 15m acc. àhold for 15m
More coming soon…
In review & in prep. studies:
àProof of concept
àFriction experiments
à‘Simple’ method for
assessing optimal load
àTraining studies…
Single'vs.'multi.
9,& þ
Acknowledgements
Coaches + Athletes
SKIPP group @AUT
Supervisors + Colleagues
Jean-Benoit Morin
Pierre Samozino
Matt Brughelli
Scott R. Brown
mcross@aut.ac.nz
@GearsetCross
cross.matt.r
Matt_Cross2
Masters thesis: AUT Summons (Matt R. Cross)
Thank'you!!
References:
Alcaraz, P. E., Palao, J. M., & Elvira, J. L. (2009). Determining the optimal load for resisted
sprint training with sled towing. Journal of Strength and Conditioning Research, 23(2), 480-485.
doi:10.1519/JSC.0b013e318198f92c
Linossier, M. T., Dormois, D., Fouquet, R., Geyssant, A., & Denis, C. (1996). Use of the force-
velocity test to determine the optimal braking force for a sprint exercise on a friction-loaded
cycle ergometer. European Journal of Applied Physiology and Occupational Physiology, 74(5),
420-427. doi:10.1007/bf02337722
Lockie, R. G., Murphy, A. J., & Spinks, C. D. (2003). Effects of resisted sled towing on sprint
kinematics in field-sport athletes. Journal of Strength and Conditioning Research, 17(4), 760-
767. doi:10.1016/s1440-2440(02)80129-3
Morin, J. B., Slawinski, J., Dorel, S., de Villareal, E. S., Couturier, A., Samozino, P., Brughelli,
M., & Rabita, G. (2015). Acceleration capability in elite sprinters and ground impulse: Push
more, brake less? Journal of Biomechanics, 48(12), 3149-3154.
doi:10.1016/j.jbiomech.2015.07.009
Petrakos, G., Morin, J. B., & Egan, B. (2016). Resisted sled sprint training to improve sprint
performance: A systematic review. Sports Medicine, 46(3), 381-400. doi:10.1007/s40279-015-
0422-8
Rabita, G., Dorel, S., Slawinski, J., Saez-de-Villarreal, E., Couturier, A., Samozino, P., & Morin,
J. B. (2015). Sprint mechanics in world-class athletes: a new insight into the limits of human
locomotion. Scandinavian Journal of Medicine & Science in Sports, 25(5), 583-594.
doi:10.1111/sms.12389
Sargeant, A. J., Dolan, P., & Young, A. (1984). Optimal velocity for maximal short- term
(anaerobic) power output in cycling. International Journal of Sports Medicine, 5(supplement 1),
124-S125. doi:10.1055/s-2008-1025973
120%
80%
40%
UL
%-HI
G-HI*
Load'(kg)
Velocity' (m.s-1)
0.5·vmax
~1.5%'bias
ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
Background: Based on recent findings regarding the mechanical determinants of sprint performance, resisted sled sprint (RSS) training may provide an effective tool for the improvement of sprint acceleration and maximal velocity. However, the volume and intensity for effective RSS training in different populations is unclear. Objectives: The primary objective was to evaluate the effectiveness of RSS training compared with unresisted sprint (URS) training, and the differential effects of sled load on RSS training outcomes. Data sources: STUDY ELIGIBILITY AND APPRAISAL: A systematic review was performed primarily using PubMed and SPORTDiscus databases. Peer-reviewed studies were accepted only if the participants used a sled towing device for a longitudinal intervention of resisted sprint training, and if RSS training was the primary difference in training intervention between groups. Effect size (ES) reported using Cohen's d was presented to compare the magnitude of effect between both dependent and independent groups. Results: A total of 11 studies fulfilled the eligibility criteria. Sled loads were prescribed either as a percentage of body mass (%BM), a targeted reduction in velocity compared with unresisted sprint velocity (%V dec) or as an absolute load (kg). RSS training with 'light' (<10 %BM or <10 %V dec) loads provide 'small' decrements in acceleration (-1.5 %, ES = 0.50) to 'moderate' improvements in maximal sprint velocity (2.4 %, ES = 0.80) in sprint-trained individuals. 'Moderate' (10-19.9 %BM or 10-14.9 %V dec) to 'very heavy' (>30 %BM or >30 %V dec) sled loads provide 'trivial' to 'extremely large' improvements in acceleration performance (0.5-9.1 %, ES = 0.14-4.00) in strength-trained or team sport individuals. Whether RSS training is more effective than URS training in the improvement of acceleration or maximal sprint velocity remains equivocal. Conclusions: RSS training is a novel training method with potential for the improvement of sprint performance, but its performance benefits over URS training remain to be conclusively demonstrated. Between-study comparisons are limited primarily by discrepancies in the training status and phase of the participants, and sled load prescription. Future work is required to define the optimal load and volume for RSS depending on the specific components of sprint performance to be enhanced.
Article
Full-text available
The objective of this study was to characterize the mechanics of maximal running sprint acceleration in high-level athletes. Four elite (100-m best time 9.95–10.29 s) and five sub-elite (10.40–10.60 s) sprinters performed seven sprints in overground conditions. A single virtual 40-m sprint was reconstructed and kinetics parameters were calculated for each step using a force platform system and video analyses. Anteroposterior force (FY), power (PY), and the ratio of the horizontal force component to the resultant (total) force (RF, which reflects the orientation of the resultant ground reaction force for each support phase) were computed as a function of velocity (V). FY-V, RF-V, and PY-V relationships were well described by significant linear (mean R2 of 0.892 ± 0.049 and 0.950 ± 0.023) and quadratic (mean R2 = 0.732 ± 0.114) models, respectively. The current study allows a better understanding of the mechanics of the sprint acceleration notably by modeling the relationships between the forward velocity and the main mechanical key variables of the sprint. As these findings partly concern world-class sprinters tested in overground conditions, they give new insights into some aspects of the biomechanical limits of human locomotion.
Article
Full-text available
A group of 15 untrained male subjects pedalled on a friction-loaded cycle ergometer as fast as possible for 5-7 s to reach the maximal velocity (vmax) against different braking forces (FB). Power was averaged during a complete crank rotation by adding the power dissipated against FB to the power necessary to accelerate the flywheel. For each sprint, determinations were made of peak power output (Wpeak), power output attained at vmax (Wvmax) calculated as the product of vmax and FB and the work performed to reach vmax expressed in mean power output (Wvmax). The relationships between these parameters and FB were examined. A biopsy taken from the vastus lateralis muscle and tomodensitometric radiographs of both thighs were taken at rest to identify muscle metabolic and morphometric properties. The Wpeak value was similar for all FB. Therefore, the average of values was defined as corrected maximal power (Wmax). This value was 11% higher than the maximal power output uncorrected for the acceleration. Whereas the Wmax determination did not require high loads, the highest Wvmax value (Wmax) was produced when loading was heavy, as evidenced by the Wvmax-FB parabolic relationship. For each subject, the braking force (FB,Wmax) giving Wmax was defined as optimal. The FB,Wmax, equal to 0.844 (SD 0.108) N.kg-1 bodymass, was related to thigh muscle area (r = 0.78, P < 0.05). The maximal velocity (vm,Wmax) reached against this force seemed to be related more to intrinsic fibre properties (% fast twitch b fibre area and adenylate kinase activity). Thus, from the Wmax determination, it is suggested that it should be possible to predict the conditions for optimal exercise on a cycle ergometer.
Article
Full-text available
Weighted sled towing is a common resisted sprint training technique even though relatively little is known about the effects that such practice has on sprint kinematics. The purpose of this study was to explore the effects of sled towing on acceleration sprint kinematics in field-sport athletes. Twenty men completed a series of sprints without resistance and with loads equating to 12.6 and 32.2% of body mass. Stride length was significantly reduced by approximately 10 and approximately 24% for each load, respectively. Stride frequency also decreased, but not to the extent of stride length. In addition, sled towing increased ground contact time, trunk lean, and hip flexion. Upper-body results showed an increase in shoulder range of motion with added resistance. The heavier load generally resulted in a greater disruption to normal acceleration kinematics compared with the lighter load. The lighter load is likely best for use in a training program.
Article
To measure leg force and power output a cycle ergometer was modified. Briefly this involved the addition of a 3 hp electric motor driving the cranks through a variable speed gearbox which allowed the pedal crank speed to be set in the range 23-180 revs/min. After the required speed was set subjects were asked to make a maximal 20 sec effort in which they attempted to speed up the ergometer, but due to the characteristics of the motorgear system this was not possible.
Article
An excessive load in resisted sprint training can produce changes in running patterns. Therefore, load control is essential to ensure the specificity of these training methods. The most common way to control it is through the percentage of velocity lost in relation to maximum velocity. The present paper describes a study that aimed to establish the load for sprint training with sled towing. The study developed a regression equation for calculating the load in the maximum velocity phase. The calculation was done with 26 athletes from the Spanish and French national levels on a synthetic track surface and with spikes. The regression equation obtained was % body mass = (-0.8674 x % velocity) + 87.99. The equation, although specific for type of surface used and sled towing characteristics, is useful in establishing the optimal load for acceleration and maximum velocity training with sled towing.
Determining the optimal load for resisted sprint training with sled towing
  • P E Alcaraz
  • J M Palao
  • J L Elvira
Alcaraz, P. E., Palao, J. M., & Elvira, J. L. (2009). Determining the optimal load for resisted sprint training with sled towing. Journal of Strength and Conditioning Research, 23(2), 480-485. doi:10.1519/JSC.0b013e318198f92c
Acceleration capability in elite sprinters and ground impulse: Push more, brake less
  • J B Morin
  • J Slawinski
  • S Dorel
  • E S De Villareal
  • A Couturier
  • P Samozino
  • M Brughelli
  • G Rabita
Morin, J. B., Slawinski, J., Dorel, S., de Villareal, E. S., Couturier, A., Samozino, P., Brughelli, M., & Rabita, G. (2015). Acceleration capability in elite sprinters and ground impulse: Push more, brake less? Journal of Biomechanics, 48(12), 3149-3154. doi:10.1016/j.jbiomech.2015.07.009
Resisted sled sprint training to improve sprint performance: A systematic review
  • G Petrakos
  • J B Morin
  • B Egan
Petrakos, G., Morin, J. B., & Egan, B. (2016). Resisted sled sprint training to improve sprint performance: A systematic review. Sports Medicine, 46(3), 381-400. doi:10.1007/s40279-0150422-8