Are We Actually Training For Speed?
Speed is often misconceptualized by many coaches and performers meaning that the way we train for speed is not as efficient as it could be, with a focus on stride frequency and stride length, rather than ground reaction force. In this essay I plan to briefly breakdown the sport (100m sprint), and then look into what we should be training for the sport, and how we should be doing this. This will allow misunderstood coaches and performers to adapt their training accordingly with support from sound, academic research.
The 100m determines ‘the fastest man/woman on the planet’ and is often the focal point of any track and field meeting. From a physical stand point it is simply who moves fastest from start to finish with the athlete drawing on the phosphagen system to create ATP through the breakdown of creatine phosphate, which has huge amounts of energy allowing us to perform at 100% (Cheetham et al, 1986). Performance in the 100m sprint is influenced by a multitude of factors including starting strategy, stride length, stride frequency, physiological demands, biomechanics, neural influences, muscle composition, anthropometrics, and track and environmental conditions (Majumdar and Robergs, 2011). I am interested in the biomechanical and aspects which will determine how we should train for the sport from a technical and physiological viewpoint.
The current focus on stride length and frequency of some coaches can be thrown away simply because successful men have a low frequency, yet the faster women have a higher frequency (Paruzel-Dyja et al., 2006). If it was the case that there was a relationship between the 2 affecting sprint performance then this wouldn’t be the case, there is clearly more to the biomechanics behind the sprint action. This thinking has probably come because of people like Usain Bolt with his incredible stride length which coaches then believe is the key to success within sprinting, which as we will see is not the case.
Research has shown that successful mechanical determinants of 100m performance were a 'velocity-oriented' force-velocity profile, explained by a greater ability to apply the resultant GRF (Ground Reaction Force) vector with a forward orientation over the acceleration phase, and a higher step frequency resulting from a shorter contact time (Morin et al., 2012). Put simply having the ability to apply a high GRF transfers into better results when matched with good technique. GRF determinants affecting sprinting physiologically are the force we can exert, and how quickly we can do this (Lockie et al., 2012), therefore we should focus on these factors in training, exerting a large force, and doing it as shorter time as possible.
All training types for sprinting do increase performance, whether it is hill sprints, weighted sprints, plyometrics etc; however some are more effective than others (Lockie et al., 2012). Incline Treadmill running was found to increase power production for the legs (Swanson and Caldwell, 2000) which was a great contributor during the accelleration phase (Chelly and Denis, 2001), however the kinematics were found to be different when running on a treadmill compared to running on track where the competitions are held (Myer et al., 2007). These altering kinematics were also shown to have a negative effect on sprint kinematics as certain muscle groups adapted to the overload (Cronin, Hansen, Kawamori, & Mcnair, 2008) required to run on an incline, rather than a flat surface which is competed on. It shows the importance of doing sports specific training which is not always the case in coaching athletics.
Lower limb strength training exercises such as the squat were shown to increase sprint performance significantly (Comfort, Haigh, & Matthews, 2012) due to the increased ability to produce a large force, nonetheless there are some downsides for sprinters as this type of training increases cross-sectional area and muscle mass