Biomechanical differences between track and football acceleration
Track VS. Football field
Head; Down VS. Up
Eyes; Down/low/ahead VS. Always up and constantly changing position to allow for processing which will likely lead to some additional movement side to side at other links of the body
Face/neck; Relaxed with no tension VS. Very, very tense (you try being chased by 11 guys and see how relaxed you are)
Arm action from the shoulders; long, often exaggerated ROM from extension to flexion VS. Short ROM to move hand quickly from about shoulder to pocket in distance with elbow close to 90 degrees. Note: the shoulders will sometimes abduct as well to put the arm in a position where it can defend off opposition (stiff-arm) or maintain balance for possible COD action
Arm action at the elbows; can extend elbow on the backswing (due to slightly longer GCT and difference in rhythmic cadence) with an aggressive punch forward of opposite arm VS. Elbow staying as close to 90 degrees as possible so arms can move quickly through their entire ROM with opposite arm sometimes carrying a ball ‘high & tight’
Hands; Relaxed (fingers cupped or loosely curled) VS. Stiff or rigid ready to attack (or again possibly holding a ball)
Hips; high flexion on front leg and nearly triple extension on the back leg VS. General hip/pelvis position staying more neutral on front leg (as center of mass is too high to allow maximum hip flexion) and very rarely even coming close to triple extension on the back leg
Knees; greater extension on the back leg (due to longer/exaggerated stride ability) VS. Quick flexion at the knee to allow for rapid turnover (and less striding out). Note: front side ROM of the knee (and really the hip as well) could be very similar all dependent on the conditions presented to the football player
Ankle; optimal dorsiflexion to plantar flexion action throughout each step i.e. on the ball of the foot with feet pointing straight VS. as much dorsiflexion to plantar flexion as one can muster but ankle must be slightly stiff to allow for quick COD at any time i.e. more full-footstrike and some toeing out action is typical
Shin (based on entire kinematic chain position); positive, positive, positive VS. As positive as we can get it but much more vertical
Differences in Coaching and Task-Intention
Common Track Idea #1: Step over the opposite knee
Difference in Football Acceleration: A wider base is typically needed at most positions in case multi-directional movement or another football tactic is required to be executed quickly
Common Track Idea #2: Programmed placement of the feet with longer steps which are then placed relatively far behind the hips (and the center of gravity)
Difference in Football Acceleration: Situational-dependent with typically fast & short steps to allow for quick turnover and the feet to be placed sometimes directly underneath the COG to allow for directional changes
Common Track Idea #3: Body being driven out low at approximately a 45 degree angle (creating a steep line of force)
Difference in Football Acceleration: Ever-changing (situation to situation) COG position and body angle to the ground
Common Track Idea #4: Allow the body to unfold naturally as the drive phase moves into acceleration
Difference in Football Acceleration: The body may need to be nearly vertical & upright after just 1-3 steps
Common Track Idea #5: Stay smooth and controlled during drive and acceleration phases. The T&F sprint athlete is not instructed to accelerate as fast as he can muster. Instead, his objective is more about what he needs to do later in the race in order to attain the best possible overall performance at the 60, 100, or 200 meter mark.
Difference in Football Acceleration: Patience to allow the tactical concerns to take care of themselves but then pedal to the floor once the decision to accelerate is made. For example, when an NFL RB sees a hole open up, he has very little time to hit it with all of his vigor and all-out acceleration. If he doesn’t do this, the hole will close quickly. Step frequency reigns supreme here.
What about COD and 360 Degree Movement?
It is intuitively obvious that the majority of movement actions that occur on the field are of multi-directional nature under open and chaotic environmental conditions which are ever-changing and never the same (i.e. the exact opposite of what occurs on a track). Based on what we’ve just discussed, it should then be apparent that under these circumstances all aspects of the BDS (Biodynamic Structure) are also considerably different (as well as variable) and this opens up an entirely separate can of worms.
Addressing this concern today would also make this the longest and most complex blog you’ve ever come across regarding American football movement. Thus, for the purpose of this blog post, most of what is to come in part 3 will be focused on discussing linear speed training application only.
However, it should be noted that these changes in task outcomes and conditions will by themselves present completely different environmental and developmental challenges. Thus, I would be amiss if I didn’t make it clear that the research throughout the years has also found the independent relationship between separate motor patterns and movement abilities (see; Salaj et al 2011, Meylan et al 2009, Little et al 2005). When we start to look at the movement actions of this nature, we know that the athlete is then much more reliant on the ability to start, stop, and then adequately change direction in numerous degrees of freedom while possessing greater body control and entirely different stability & mobility concerns. Furthermore, the physical attributes contributing to the performance of the specific tasks are also distinct. Thus training tasks directed towards each movement ability and those correlating attributes should be specifically more directed components at least when working with athletes of higher levels of mastery.
Next time, in Part 3 of 3, I will follow through with my promise when I discuss a few of the distinct differences in the conceptual ideas for the proper preparation and training of each specific type of acceleration task.