It was agreed on the old forum that ground forces are a key to max velocity.
Given the importance of ground forces towards max velocity, as coaches how do we get athletes to generate higher GRF?
As I recall, strength development will increase GRF.
Am i right in thinking that power training will result in improvements? Higher verticle force to the ground???
any other thoughts on this
I would think getting stronger/more powerful in any way would result in increased GRF.
Getting strong BUT maintaining tendon and muscle compliance is the key. High viscosity in muscle and tendons increases ground contact time. A tendon can either be stiff or compliant. The stiffer a tendon, the more energy needed to stretch it. We know that GRF is directly affected by tendon stretch shortening in co-operation with muscle. Stiff tendons are akin to short thick elastic bands whilst compliant tendons are akin to long thin elastic bands. You want long thin tendons or tendons that have compliant characteristics. Stiff tendons produce great force and but need alot of strength to pre-stretch them. As a consequence the return of energy at ground contact time will be less efficient and loss of energy will occur through heat dissipation. On the other hand, a more compliant tendon will need less strength to pre-stretch it. It will have a lower stiffness but greater elasticity and low hysteresis (loss of energy that occurs between stretch and recoil).
We also want muscle to be less viscose and more elastic.
The key to achieving this is through plyometric training and stretching. If you want to decrease ground contact and enhance GRF then it is important that you enhance tendon compliance by stretching but at the same time, enhance compliance through plyometrics and sprinting. Weight training will improve stiffness but you don’t want excessive muscle tone and stiffness in tendon and muscle because of increased hysteresis, so to counteract this a purposeful stretching program that includes some ballistic , PNF and static stretching and massage is the key to aiding in the improvement of GRF and decreasing GCT. The more viscose the tendons and muscles, the lower the GCT. The more compliant and elastic the muscles and tendons, the lower the GCT and the higher the GRF.
It is important to note that working on improving flexibility of the hamstrings and calf/achilles complex is likely to aid in increasing GRF and decreasing GCT.
Good post!
I agree with what you say in theory, but when applied plyometrics can be difficult to integrate with sprint training because of DOMS. I prefer olympic lifts because they can develop power without placing ^ eccentric loads.
It is important to note that working on improving flexibility of the hamstrings and calf/achilles complex is likely to aid in increasing GRF and decreasing GCT
Any data to back this up? Thanks.
Do a search on the internet to see if there is data.
I clearly stated that improving compliance is likely to decrease GCT I didn’t say that it did I said likely. The evidence suggests that this is probably the case. There is a slew of evidence suggesting that this is part of the answer to decreasing GCT increasing GRF. Do a search yourself and see.
Why are you getting DOMS? If you are getting DOMS then,
A/ Prior exposure has been woefully low.
OR
B/ You are doing too much volume.
You should not be experiencing DOMS from plyo .
In fact there shouldn’t be any DOMS from a good sprint training program after the initial loading.
If olympic lifts were the key then Dimas et al would be 100m champions.
Thats not so say that OL do not have their place but plyo is needed by many to improve.
I clearly stated that improving compliance is likely to decrease GCT I didn’t say that it did I said likely. The evidence suggests that this is probably the case. There is a slew of evidence suggesting that this is part of the answer to decreasing GCT increasing GRF. Do a search yourself and see.
In my experience with the force mat only plyometric kind of work (acutely and long term) as well as maximal weight training (acutely) improved both the GCT and GRF. Maximal strength training improved GRF in the short and long term, too. Stretching diminished the GRF and lengthened the GCT acutely but I don’t know if stretching specifically some muscles would result in better GCT and GRF in the long term. That’s why I asked; I thought you had done some work with the force mat, too.
When was the stretching done immediately before the test? Or was it kept well way from the jump mat tests? Immediately decreases potentation. A program of stretching where sessions are done hours before and hours after will not elicit the same effect. Stretching an hour to minutes before may increase contact time and decrease GRF. Especially for hurdle hop and cmj tests. I have a contact mat also and am planning on using a chrono jump set up soon.
Which muscles were stretched prior to the test? How many minutes prior to the test? How did you measure the Z component of the GRF using a contact mat?
Stretching immediately before the test or an explosive event will affect the performance. But combine strength and resistance training with stretching will improve GRF and GCT. Stretching will decrease loss of energy through heat dissipation (hysteresis) and improve the compliance of a tendon. Max strength will affect tendon stiffness, power and the CNS along with a myriad of other benefits that have been id and is tiresome to mention again. Plyo will improve stiffness hysteresis and the CNS and another bunch of benefits thrown in. BUT too much muscle viscosity and stiffness may develop over time if not managed with massage and stretching.
Stretching immediately before an event or test will increase the spacing between actin myosin filaments, decreasing the muscle belly stiffness and inhibiting CNS potential immediately before. Stretching over time will affect compliance of tendon and decrease muscle viscosity. What must be said is that excess and mis timed implementation with any of these training modalities will not lead to the desired effect. NO ONE training method is the key, but tendon compliance is very important for sprinters.
Stretching immediately before an event affects CNS potential. Flexibility training overtime improves tendon compliance. This will likely lead to faster shortening of tendons which will lead to less shortening of the muscle fibers which paradoxically IMPORVES stiffness overall. This is because the tendon will shorten faster leaving the muscle to maintain stiffness. This is a crude explanation of the Hill muscle tendon complex but I hope it is clear.
Exactly - well put.
Things in a well thought out program won’t change drastically from day to day wk to wk and allow DOMS to shift in and destroy the hard work you have been putting in.
If you want to add in Plyro’s - there is a slow, steady painless way to do so. examples of which are clearly shown in the Vancouver download - or books such as Tudor O. Bompo’s Power training for sport.
I do not agree, if anything the evidence suggests high levels of stiffness are associated with rapid transmission of force. Most likely an optimal level exists for sprinting somewhere along the compliance-stiffness continuum, but certainly favouring stiffness.
It would be interesting to see what Charlie has to say on this, or others ???
I disagree with you. Triple jumpers have higher levels of muscle stiffness than sprinters on average… are they faster? I am not talking about being as flat as a pancake but too much stiffness is not good. I have evidence to back am my stance but to be honest I think that people should do their own research to refute what I am saying before asserting that I am wrong. What evidence DO YOU have to say that my stance is wrong? YES muscle stiffnees is essential in fact it was I WHO posted on the link between speed endurance and muscle stiffness. But stiffness in which part of the muscle tendon complex? How is it achieved show me your evidence to refute my stance and I will gladly back down.
Stiffness with low compliance of TENDON is just as bad as low stiffness. Stiffness with COMPLIANT tendons leads to HIGHER musculo tendon complex stiffness if we follow the hill model.
Distance runners have STIFFER tendons than sprinters. Sprinters have more compliant tendons allowing more force applied hence less GCT. Stiffer tendons lead to energy loss through heat.
A more compliant tendon is the key. I AM NOT saying that stiffness is not important I am saying that an MTC where the tendon is more compliant or elastic is the way forward. If you have very stiff tendons then this causes bothe the muscle fibers and tendons to shorten at the same speed leading to loss of energy through heat loss and hence longer GCT. The key is to stay SUPPLE in the TENDONS but increase strength.
Try this get a thick short elastic band and a long thin elastic band. Which is more compliant which is stiffer which one needs more effort to stretch? Which one has a faster stretch shortening? You can improve tendon compliance through stretching, the evidence exists.
When was the stretching done immediately before the test?
As I wrote, acutely, meaning, right before the test. I know the outcome was obvious, but I did the test to show something to one of my athletes.
How did you measure the Z component of the GRF using a contact mat?
It’s a rebound test, the software of my mat, which was developped by one of Prof. Bosco pupils, has an algorithm to calculate GRF.
Flexibility training overtime improves tendon compliance. This will likely lead to faster shortening of tendons which will lead to less shortening of the muscle fibers which paradoxically IMPORVES stiffness overall. This is because the tendon will shorten faster leaving the muscle to maintain stiffness. This is a crude explanation of the Hill muscle tendon complex but I hope it is clear.
To back this up:
Muscle - tendon unit mechanical and morphological properties and sprint performance.
Stafilidis S, Arampatzis A.
Institute of Biomechanics and Orthopaedics, German Sport University of Cologne, Cologne, Germany.
The objective of this study was to determine whether sprint performance is related to the mechanical (elongation - force relationship of the tendon and aponeurosis, muscle strength) and morphological (fascicle length, pennation angle, muscle thickness) properties of the quadriceps femoris and triceps surae muscle - tendon units. Two groups of sprinters (slow, n = 11; fast, n = 17) performed maximal isometric knee extension and plantar flexion contractions on a dynamometer at 11 different muscle - tendon unit lengths. Elongation of the tendon and aponeurosis of the gastrocnemius medialis and the vastus lateralis was measured using ultrasonography. We observed no significant differences in maximal joint moments at the ankle and knee joints or morphological properties of the gastrocnemius medialis and vastus lateralis between groups (P > 0.05). The fast group exhibited greater elongation of the vastus lateralis tendon and aponeurosis at a given tendon force, and greater maximal elongation of the vastus lateralis tendon and aponeurosis during maximum voluntary contraction (P < 0.05). Furthermore, maximal elongation of the vastus lateralis tendon and aponeurosis showed a significant correlation with 100-m sprint times (r = -0.567, P = 0.003). For the elongation - force relationship at the gastrocnemius medialis tendon and aponeurosis, the two groups recorded similar values. It is suggested that the greater elongation of the vastus lateralis tendon and aponeurosis of the fast group benefits energy storage and return as well as the shortening velocity of the muscle - tendon unit.
Distance runners have STIFFER tendons than sprinters. Sprinters have more compliant tendons allowing more force applied hence less GCT. Stiffer tendons lead to energy loss through heat.
I only found this study, but it says the opposite:
Mechanical properties of the triceps surae tendon and aponeurosis in relation to intensity of sport activity.
Arampatzis A, Karamanidis K, Morey-Klapsing G, De Monte G, Stafilidis S.
German Sport University of Cologne, Institute of Biomechanics and Orthopaedics, Carl-Diem-Weg 6, 50933 Cologne, Germany. Arampaztis@dshs-koeln.de
The purpose of the present study was to investigate whether the mechanical properties (i.e. force strain relationship) of the triceps surae tendon and aponeurosis relate to the performed sport activity in an intensity-dependent manner. This was done by comparing sprinters with endurance runners and subjects not active in sports. Sixty-six young male subjects (26+/-5 yr; 183+/-6 cm; 77.6+/-6.7 kg) participated in the study. Ten of these subjects were adults not active in sports, 28 were endurance runners and 28 sprinters. All subjects performed isometric maximal voluntary plantar flexion contractions (MVC) on a dynamometer. The distal aponeuroses of the gastrocnemius medialis (GM) was visualised by ultrasound during the MVC. The results showed that only the sprinters had higher normalised stiffness (relationship between tendon force and tendon strain) of the triceps surae tendon and aponeurosis and maximal calculated tendon forces than the endurance runners and the subjects not active in sports. Furthermore, including the data of all 66 examined participants tendon stiffness correlated significantly (r=0.817, P<0.001) with the maximal tendon force achieved during the MVC. It has been concluded that the mechanical properties of the triceps surae tendon and aponeurosis do not show a graded response to the intensity of the performed sport activity but rather remain at control level in a wide range of applied strains and that strain amplitude and/or frequency should exceed a given threshold in order to trigger additional adaptation effects. The results further indicate that subjects with higher muscle strength possibly increase the margin of tolerated mechanical loading of the tendon due to the greater stiffness of their triceps surae tendon and aponeurosis.
May be we need to consider that different compartments of the human body require different engines / tyres. Knee complex, hip ankle etc?
I thought you were argueing that stiffer tendons = higher/faster ground rection forces whereas the study above seems to add support to the opposite?
When you gain flexibility through an effective stretching program is it because the muscle or the tendon becomes more pliable?
It’s only rumours and hardly scientific but Kadour Ziani stretches for hours daily and his vertical leap is crazy plus he is skinny as a rake and imo relies very much upon his tendon elasticity.