Maximal Strengths role within Mixed Martial Arts
The Physiological Adaptations of Maximal Strength Training within Male Professional/Elite Mixed Martial Artists
Mixed martial arts (MMA) is a combination/hybrid of various other combat sports including, Brazilian jiu-jitsu, wrestling, boxing, kickboxing, taekwondo, judo and many others (Buse, 2006). The Ultimate Fighting Championship (UFC) is seen as the pinnacle of the sport in the western world, despite other high-profile organisations such as ONE FC, Bellator, ACA, Rizin, Cagewarriors etc also showcasing high level professional mixed martial artists. Competition performance in MMA can be directed towards the following attributes, physical, technical, tactical and psychological. These facets of performance are intertwined with differences between weight classes, fighting styles and genders creating a unique spectrum of skills and attributes needed to excel in the sport (UFC PI Handbook).
MMA consists of 3 x 5-minute rounds or in the case of a main event or championship fight 5 x 5-minute rounds of competition with a minute rest period between rounds (Miarka, Del Vecchio, Camey & Amtmann, 2016). The average fight time noted in the UFC (10.43 in 2017) has increased as the sport has progressed over the years potentially due to better match making or more robust athletes (UFC PI Handbook). It is important to distinguish that there is a linear relationship between weight classes and fight duration, with male heavyweights having the shortest times 8.02 average compared to the female strawweight’s with an average bout length of 12.35 (UFC PI Handbook). Key performance indicators also vary between male and female bouts, these differences may impact training modalities and sought-after physical characteristics between male and female mixed martial artists. Key performance indicators for males are highly linked to striking techniques (total strikes, significant strikes etc) and the amount of ground control/control per round (UFC PI Handbook).
A duration of a bout can last 15-25 minutes which would indicate that the aerobic energy system is used during the event based on general sport science guidelines. However, it is during the high intensity bursts of 8-14 seconds within those time frames that the bout is most likely to be decided (UFC PI Handbook) making it essential to develop anaerobic pathways in order to manifest explosive strength and power repeatedly during a bout, this would encourage coaches to develop the technical/tactical skills of striking and groundwork and the physical attributes to emphasise the phases of high intensity activity (Miarka, Vecchio, Camey & Amtmann, 2016) (Del Vecchio, Hirata & Franchini, 2011).
Within mixed martial arts strength is expressed in a variety of ways, speed/speed-strength at one end of the spectrum and maximal strength at the other end (force time curve reference). High force generating capabilities are required in order to manipulate the mass of an opponent, with-stand collisions or underpin higher velocity movements such as strikes, throws and takedowns. It is proposed that rate of force development (RFD) is one of the most important physical characteristics within sport, it may be the most important physical characteristic outside of technical/tactical attributes (Taber, Bellon, Abbott & Bingham, 2016). Maximal strength is the greatest amount of force produced regardless of time, other strength qualities are reliant on the underpinning ability to produce maximum strength, maximal strength with provide an upper limit for power production (UFC PI Handbook) (Taber, Bellon, Abbott & Bingham, 2016). Explosive movements in mixed martial arts such as striking, kicking and takedowns require high amounts of RFD, research would suggest that maximal strength has the greatest effect on voluntary RFD variability (90%) >90ms which corresponds with most dynamic movement skills in mixed martial arts, it is important to note striking occurs within <200ms and other training methods may be needed to facilitate the improvements in higher velocity actions (Anderson & Aagaard, 2006).
Currently there is limited research on physiological determinants/profiles and adaptations of training methods within MMA competitors compared to the Olympic sports which make up the sport of MMA such as wrestling, judo, boxing and taekwondo (Franchini, Del Vecchio, Matsushigue & Artioli, 2011; Yoon 2002; Chaabene et al 2014; Bridge, Santos, Chaabene, Pieter & Franchini 2014). Within the literature which is available, Lachlan, Beckman, Kelly & Haff, (2016) study on high and low level mixed martial artists found that higher levels of maximal lower body neuromuscular capabilities (maximal strength, peak power, velocity and impulse) were found to be the differentiating factor between the higher-level competitors and the low-level competitors. In a study by Bagley et al, (2016) they found that elite mixed martial artists had a homogenous muscle fiber type, predominantly consisting of fast twitch muscle fibers superior to both untrained and trained males. In addition to this it was found that elite mixed martial artists have a relatively small myonuclear domain size compared to untrained men, however it is important to note this research is limited due to the low sample size and control groups used for comparison. These studies indicate that there are potentially sought-after attributes for mixed martial artists, both morphological and neurological adaptations from maximal strength training can influence these sought-after characteristics.
High resistance maximal strength training is used to improve sports performance, improve musculoskeletal health and alter body aesthetics/body composition (Folland & Williams, 2007). Changes in muscular strength are attributed to both morphological and neurological adaptations to strength training. Due to the variability in athletes which participate in MMA and their backgrounds there is variability in the training prescriptions for the athletes in question which need to be individualised alongside technical/tactical coaching. Grappling based competitors’ muscular actions in combat are physiologically high force movements which by increasing maximal strength would carry over to performance increases, however for striking based athletes the higher velocity actions of the force/velocity curve e.g. speed/strength seem to indicate superior sporting performance (James, Haff, Kelly & Beckman, 2016). Regardless of sporting background maximal strength training will have positive effect on mixed martial arts performance, whether a primary transfer to grappling type scenarios or movements that require high forces or as a tertiary transfer by being a underpinning quality that can potentiate RFD, impulse, momentum, velocity and power (Taber, Bellon, Abbott & Bingham, 2016).
Improvements in maximal strength are a by-product of a well-structured resistance training program, by manipulating training variables resistance training can elicit physiological adaptations such as neuromuscular recruitment and increased cross sectional area. Training variables which are linked to improvements in maximal strength are training volume and load (Peterson, Rhea & Alvar, 2004). The intensity of training loads for high level athletes is markedly higher than lower level athletes with less training history, a mean training load of 85% one repetition maximum seems a reliable intensity in order to drive performance improvements in maximal strength in trained athletes (Peterson, Rhea & Alvar, 2004). Monitoring % of one repetition maximums or repetition targets is important within the overall framework of an athlete training program to avoid overreaching/overtraining when unplanned (Thompson, Rogerson, Ruddock & Barnes, 2019). It is also imperative that coaches vary intensity and volume throughout a training program in order to elicit a physiological response (periodization), there seems to be a standardised dose-response trend in the literature (Peterson, Rhea & Alvar, 2004) although it’s important to consider dose/volume on an individual basis depending on the athletes competition calendar, technical/tactical training volume and weight management strategy/complications within MMA. There is huge scope for variability in loads used during maximal strength training and periodisation in general in a chaotic and unpredictable sport such as mixed martial arts. The premise that a given percentage trains a certain physiological attribute is based on physiology text/research although in practice training prescriptions can become more complex/uncertain. It is common for elite weightlifters under Boris Sheiko to predominately lift loads under 80% yet they are some of the strongest athletes in the world, there are paradoxes within training prescription and a more pragmatic approach may be needed (Jovanovic, 2020). In MMA given the uncertainty of training schedules, competition bouts, injury history etc, make it essential to take the athlete as an individual into training prescription, even for maximal strength training, although estimations of conventional rep ranges and percentages are a useful starting point.
Strength training has been found to have a profound and meaningful effect on all biological systems (Egan & Zeirath, 2013), including morphological adaptations, neurological adaptions and also hormonal responses. Morphological changes that can occur as a result of maximal strength training include; muscular hypertrophy, changes in fiber type, changes in muscular architecture/pennation angles, density of skeletal bone and muscle and changes in connective tissue (tendons and ligaments etc) (Folland & Williams, 2007).
Muscular hypertrophy can be measured in two distinct ways, anatomical cross-sectional area (ACSA) via scanning techniques (MRI, CT, ultrasound etc) and physiological cross-sectional area (PCSA). PCSA may be important to measure the muscles ability to produce contractile force than ASCA however it can be harder to measure reliably (Folland & Williams, 2007). Adaptations to strength training are a by-product of a response to signalling caused by training, Spurway & Whackerhage, (2006), devised a 5-step process explaining this; anabolic signal detected, altered release of growth factors, gene expression, protein synthesis, and satellite cell proliferation and differentiation. During strength training microdamage occurs to the architecture of the muscle cells, this signal stimulates proliferation of the satellite cells, satellite cells are precursors to myofibers, the satellite cells add to the nuclei and myofibrils in order to contribute to synthesis of contractile protein. The addition of new contractile protein increases the PCSA of the muscle (Brummit & Cuddeford, 2015). Many weight class athletes within MMA will want to avoid any additional sarcoplasmic hypertrophy (additional fluid and non-contractile muscle) and thus training methods and nutrition should be adjusted accordingly.
An important consideration for the MMA athlete is that there are weight classes to be met, this will dictate the amount of hypertrophy the athlete may or may not want to accrue in a given training cycle. This is an individual response to training depending on the athlete’s current body composition and previous training experience. The amount of volume needed to stimulate a hypertrophic response can vary between individuals, the amount of stimulus needed to enable a hypertrophic response and nervous system response will vary depending on training history (Anderson & Aagaard, 2010). This coincides with Schoenfeld et al’s (2019) study on training volumes relationship with strength increases and hypertrophy which found that low volume strength training was able to improve strength and endurance in participants, however hypertrophy was determined by the training volume used in a dose-dependent relationship.
Long term heavy resistance training increases the synthesis of myofribular proteins, this increase in cross sectional area is predominantly made up of fast twitch muscle fibres as maximal strength training induces greater fast twitch muscle hypertrophy than slow twitch hypertrophy (Tesch, 1988). As stated by Bagley et al (2016) which although a small study, characterised elite performance in MMA to be associated with a high level of fast twitch fibers, which may indicate that this preference is potentially trainable. It is important to note that maximal strength training converts type 2x fibers which have the fastest contraction velocity to type 2a fibres (variations in fast twitch muscle fibre). This may seem unfavourable at a cellular level identifying singular muscle fibers however when assessing the performance capability of the whole system as a by-product of training, there are increases in contractile strength, power and RFD of the trained muscle groups (Anderson & Aagaard, 2010).
Another morphological adaptation to maximal strength training is the effect it has on non-contractile tissues of the body (ligaments, tendons, bone etc). Injury incidence in MMA is greater than all other combat sports (Lystad, Gregory & Wilson, 2014). The most common sites/joints of injury in MMA are the knee, shoulder and hand/wrist (UFC PI Handbook). Strength training can promote growth and help strengthen ligaments, tendons, tendinous attachments, joint cartilage and the connective tissue sheaths within muscle (Fleck & Falkel,1986) (Grzelak, Podgorski, Stefanczyk, Krochmalski, & Domzalski, 2012) . Resistance training increases the collagen synthesis rate in fibroblasts, similar to muscle protein synthesis that occurs during muscular hypertrophy. Collagen is an important component of the extracellular matrix of muscles and tendons and is responsible for their ability to transmit and absorb force (Oertzen-Hagemann et al, 2019). Bone mineral density (BMD) is an indicator of bone health, bone is dynamic mineralised connective tissue used for numerous functions within the body, is particular protecting vital organs and loading bearing movements (Antonio et al, 2018). Bone mineral density can be improved as an adaptation to resistance training (Hong & Kim, 2018) mechanical load must be greater than which the body is used to, in order to drive adaptation. Professional MMA fighters have the highest bone mineral density comparatively to other sports (excluding American football), in particular note they have a substantially higher bone mineral density, then other combat sports (Antonio, et al, 2018). Further research is needed in order to determine if higher bone density in professional fighters is due to self-selection or training practices, is their genetic predisposition to high BMD a reason they are able to excel at the sport, or has the sports loading via collisions, strikes and resistance training practices contributed to the findings (Antonio et al, 2018).
In addition, maximal strength training has been shown to have a positive effect on favourable hormones. Heavy resistance training has shown to bring about an increase in the concentration levels of hormones such as IGF-1, testosterone and insulin (Jones, Rutherford & Parker, 1989). Lower levels of body fat and greater levels of fat free mass are associated with higher testosterone levels (Gates, Mekary, Chiu, Ding, Wittert & Araujo, 2013), based on previous literature within other combat sports, fat free mass/low bodyfat levels have been shown to be consistent across the board in elite performers (Franchini, Del Vecchio, Matsushigue & Artioli, 2011; Yoon 2002; Chaabene et al 2014; Bridge, Santos, Chaabene, Pieter & Franchini 2014). Due to the controversial topic of weight cutting in mixed martial arts (Barley, Chapman & Abbiss, 2019), an increase in fat free mass and low levels of bodyfat may be beneficial to help the weight cutting process. By adding resistance training to a calorie restricted diet more fat free mass is preserved during weight loss (Hunter, Byrne, Sirikul & Gower, 2008). There may also be merit to having an increased amount of muscle mass during the water cut process, MMA athletes lower bodyweight fight week by manipulating water, electrolytes and glycogen stores (Barley, Chapman & Abbiss, 2019). Muscle mass is associated with having a high glycogen content and as a by-product water content (Jensen, Rustad, Kolnes & Lai, 2011), this may indicate that athletes with more muscle mass may be able to drop a greater proportion of weight from glycogen stores/water associated rather than dehydration from other bodily structures, although further research is needed.
Various neurological changes also occur as an adaptation to strength training that are worth touching on. Increases in strength occur quickly within a training program, this is often due to changes that occur at the cortical and spinal level. Maximal strength training improves muscular force short term by increasing motor neuron recruitment and rate coding (Del Vecchio et al, 2019). Small motor units are usually recruited appropriately for the task at hand e.g. easier the task less recruitment, this is due to the size principle where smaller motor units are recruited first due to their greater excitability (Dideriksen & Farina, 2013), as a by-product of maximal strength training larger motor neurons are recruited faster due to greater firing rates (rate coding) within the neurons, this enables the athlete to express a great amount of strength. Maximal strength training also improves synchronisation, which is the capacity to contract motor units simultaneously with little delay (Bompa & Buzzichelli, 2015). These improvements in intramuscular coordination can translate the sporting skill as long as the athlete has technical proficiency the increased motor unit recruitment will cross over. Intermuscular coordination (the nervous systems ability to coordinate) is also improved as a by-product however this attribute is more specific to the task at hand, therefore the athletes get better at the skill of lifting but not their sports skill (Bompa & Buzzinchelli, 2015).
Professional MMA fighters need to be robust and high performing athletes, the primary adaptations to maximal strength training covered have been morphological, often the major benefits to athletes in weight class sports are regarded as neuromuscular, however given the physiological determinants of professional fighters and other elite combat sports athletes morphological adaptations appear to be as important. In particular the conversion of type 2 muscle fibers (Bagley et al, 2016) and positive structural changes including the ability to build or preserve fat free mass, the ability to withstand injury, strengthening tendons, ligaments and improving bone density. These adaptations along with favourable hormonal changes as a adaptation to strength training are essential to the competitive MMA athlete. The proposed benefits on maximal strength training on the neuromuscular system work in synergy with morphological changes, both complement each other and neither are stable or at their full potential (Bompa & Buzzinchelli, 2015). The body’s systems ability to adapt to a stimulus is not in isolation, neuromuscular changes can enable greater morphological changes, e.g. great intermuscular coordination, enables the technical lift to be completed with more load, this in turn leads to greater structural/morphological changes over a training period. Equally, greater muscular hypertrophy will allow the athlete to have a greater cross-sectional area (ACSA/PCSA) and thus the potential to have more motor units to recruit during weight lifting exercises or sporting skills. Due to the nature of MMA and its uncertainty, weight classes, fighting styles, individual responses to training, nutritional interventions, competition periods etc percentage loads and volumes of maximal strength training need to be constantly adjusted on an individual basis in order to facilitate performance improvements ( RFD, power, strength, robustness etc) as an response to both neuromuscular and morphological physiological adaptations. Improving these will enable MMA athletes to have a greater chance of excelling in the 8-14s high intensity bursts of effort that often dictate a fight (UFC PI Handbook).
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