Evidence of a Double Peak in Muscle Activation to Enhance Strike Speed and Force: An Example With Elite Mixed Martial Arts Fighters

Abstract

The main issue addressed here is the paradox of muscle contraction to optimize speed and strike force. When muscle contracts, it increases in both force and stiffness. Force creates faster movement, but the corresponding stiffness slows the change of muscle shape and joint velocity. The purpose of this study was to investigate how this speed strength is accomplished. Five elite mixed martial arts athletes were recruited given that they must create high strike force very quickly. Muscle activation using electromyography and 3-dimensional spine motion was measured. A variety of strikes were performed. Many of the strikes intend to create fast motion and finish with a very large striking force, demonstrating a "double peak" of muscle activity. An initial peak was timed with the initiation of motion presumably to enhance stiffness and stability through the body before motion. This appeared to create an inertial mass in the large "core" for limb muscles to "pry" against to initiate limb motion. Then, some muscles underwent a relaxation phase as speed of limb motion increased. A second peak was observed upon contact with the opponent (heavy bag). It was postulated that this would increase stiffness through the body linkage, resulting in a higher effective mass behind the strike and likely a higher strike force. Observation of the contract-relax-contract pulsing cycle during forceful and quick strikes suggests that it may be fruitful to consider pulse training that involves not only the rate of muscle contraction but also the rate of muscle relaxation.

Trunk muscle activation during golf swing: Baseline and threshold

“…Jöllenbeck, 2000;Wong and Ng, 2005;Soylu and Arpinar-Avsar, 2010), instead of complex dynamic actions. Due to the phases that make up complex actions, the EMG is associated with qualitative changes from one phase to the following phases, which suggests different muscles assuming different roles throughout motor skills (Cordo et al 2003;McGill et al, 2010). In a golf swing, which is a complex dynamic action, so far there have been few studies on temporal parameters (Horton et al, 2001;Cole and Grimshaw, 2008).…”

“…RA -rectus abdominis; EO -external oblique; ES -erector spinae. execution phases, the contraction relaxing contraction relationship could affect EMG behavior, due to the stretch-shortening cycle properties (McGill et al, 2010). For a golf swing, the transition from backswing to downswing is related to energy storage and transfer, in order to favor segment acceleration, followed by deceleration before impact (Cheetham et al, 2008).…”

“…For a golf swing, the transition from backswing to downswing is related to energy storage and transfer, in order to favor segment acceleration, followed by deceleration before impact (Cheetham et al, 2008). The double peak phenomenon is associated to different actions in those phases (McGill et al, 2010). The first peak can be associated with the action of stabilizing the trunk before movement starts, whereas the second is related to the dynamic action with its maximum peak occurring next to impact.…”

“…The different phases that make up complex motor skills would require different approaches for the meaning of EMG signal. McGill et al (2010) characterizing a double-peak intensity phenomenon in motor skills such as kicking in martial arts. This phenomenon could be associated with the muscular actions during the different phases of those tasks.…”

“…For golf swinging several phases can be discriminated, such as the preparation (backswing), execution (downswing) and result (follow-through). Some authors have opted to include descriptive and qualitative movement analysis, due to activity characteristics and particular muscle actions (Hirashima et al, 2002;McGill et al, 2010).…”