Fifteen years ago I wrote my BSc dissertation on how carrying a pole-vaulting pole affected an athlete’s sprinting kinematics. The athlete was obviously affected by the weight and size of the pole, but carrying it also changed the role that the arms played in the sprinting model. This altered model interested me and if I had carried on in university to do a masters degree I’m sure I would have further investigated the subject. As well as pole-vaulters there are many athletes who use a modified sprinting model, for example rugby players carrying a ball or amputees who use prosthetic limbs. Since then there have been a number of papers exploring these topics, including a recent one by Beck and Grabowski that I discovered via the power of Twitter:
An e-mail to one of the authors led me to digging out my dissertation and then to diving deep into a Research Gate black hole. The purpose of this blog is to try and solidify some of my thoughts on what I’ve been reading. This is not a scientific paper, so if you’re interested in this stuff I highly recommend you go and read some of the articles that I’ll list at the end.
My research found that carrying a pole resulted in the athletes having a lower peak velocity than when running ‘free’. There is no real surprise here and it is backed up by Adamevski and Dicwach, 1992; Frère, 2010; Frère et al, 2009, 2017.
My main findings were that the athletes displayed a decrease in stride length, but not stride frequency, decreased angular velocities at the hip and knee and a delayed recovery of the trailing leg.
This matches nicely with Frère et al, 2009 who stated that:
“The results showed that carrying a pole during the run-up had a significant effect on the horizontal velocity and that the decrease in this velocity was correlated with a significant decrease in stride length, whereas the stride rate was relatively unchanged.”
The Frère paper only looked at the mechanics of the right leg, in order to reduce parallax errors, something which I combated by using two cameras to create a 3D model of the athlete. (These days VICOM systems can do in an instant what took me months to achieve.) The one side they did look at though, again matched the findings of my study:
“The pole-side cycle showed that the maximal hip flexion angle (P<0.01) and the maximal knee flexion angle (P<0.05) were significantly smaller during run-ups with pole than without…”
What my 3D model allowed me to do was the look at asymmetries in the technique. I found that the athletes rotated their trunks more whilst carrying a pole, an action which would normally be countered by the use of the arms. In addition the right shoulder was held back slightly by the pole, which led me to write this in my abstract:
“This, together with the asymmetrical variation seen in both the angular displacements and velocities of the hips and knee suggest that the mass of the pole is acting eccentrically to the centre of mass of the athlete. This creates a torque causing an asymmetrical loading of the legs.”
Unfortunately I wasn’t able to measure or test this asymmetrical loading theory, which is why I was very interested to read Beck and Grabowski’s paper. Using a force plate equipped treadmill they were able to directly measure the ground reaction forces of someone with a very asymmetrical style - an athlete with a unilateral transtibial amputation.
This athlete used ‘passive-elastic carbon-fibre running specific prosthetic’ (more commonly called a blade) to facilitate running. One interesting point, which I hadn’t thought about before, was that the blade acts like a spring and is longer when unloaded than when he is standing with his weight on it. The distance from the greater trochanter to the floor during standing was 1.03m on his unaffected leg, compared to 1.09m on an unloaded affected leg.
“….the present study’s athlete exhibited more asymmetric spatio-temporal and ground reaction forces than those of non-amputees at matched running speeds. For example, at 9.5 ± 0.42 m/s, non-amputees exhibit average step length and stance average vertical GRF asymmetries of 1.7 ± 3.2 and 2.0 ± 4.5% (±SD), respectively. Whereas at 9.21 m/s, the present study’s athlete exhibited step length and stance average vertical GRF asymmetries of 11.9 and 31.%, respectively.”
One thing that many of the papers mentioned, and I’m sure the amputee athlete would agree, is that running under altered circumstances/with a different biomechanical model is a skill. It has to be learned and trained in order to be performed at a high level. One paper looking at carrying a rugby ball (written by some very famous names in the industry - Matthew Barr, Jeremy Sheppard, Tim Gabbett and Robert Newton) found only small differences in max speed for international players with and without a ball, but stated:
“The decrements in speed from B2H [ball in 2 hands] conditions were much less for the international players when compared with previously reported data from amateur club players. Coaches working with rugby players should regularly incorporate sessions focussed on speed development, as well as including B1H [ball in one hand] and B2H as part of a speed testing battery.”
“It may be a trainable skill and elite rugby players, who presumably are accustomed to this skill, might show minimal performance decrements while sprinting with a ball. If this was the case, then performing sprint training while carrying a ball may need to be a key focus of training in sub-elite players.”
Similarly Frère et al, 2017 (including another famous name in this field - JB Morin) stated:
"This specifically opens the question about the respective effects of the additional mass (of the pole), the arm swing restriction or the level of expertise (i.e. is it still true for world-class athletes?). Also, these results highlight a potential need to optimise the sprint training program to diminish this force-deficit associated with pole carriage. Such hypothesis emphasises the interest in regularly monitoring the force-velocity relationships in sprinting with and without pole. Bringing these two profiles closer may help increase the running top speed at take-off which might be beneficial for the final performance.”
In conclusion an S&C coach looking to maximise transfer between the weight room and sports performance or a physio/sports therapist/S&C rehabbing an injured player should take into account altered sprint biomechanics when designing a program. Especially in pole-vaulting and other highly technical sports we should involve the technical coaches and biomechanists, to ensure correct carrying technique, something the fitness coach or medical staff may not be 100% familiar with. The athlete’s support team should really be a team.
Some references that may be of interest:
Barr, J.M. Gabbett, T. Sheppard, J. Newton, R.U. (2015) The effect of ball carrying on the sprinting speed of international Rugby Union players. International Journal of Sports Science & Coaching. February 2015.
Beck, O.N. & Grabowski, A.M. (2017) Case studies in physiology: The biomechanics of the fastest sprinter with a unilateral transtibial amputation. Journal of Applied Physiology, 2017.
Frère, J. Sanchez, H. Homo, Rabita, G. Morin, JB. & Cassirame, J. (2017) Influence of pole carriage on sprint mechanical properties during pole vault run-up. Computer Methods in Biomechanics and Biomedical Engineering, 20:sup1, 83-84.
Frère, J. Chollet, D. & Tourney-Chollet, C. (2009) Assessment of the influence of pole carriage on Sprint Kinematics: A case study of Novice athletes. International Journal of Sports Science and Engineering. Vol. 03 (2009) No. 1, 3-10