As a consequence of normal physical activity, it is estimated that 1-2% of skeletal muscle tissue is synthesised and broken down on a daily basis (Rasmussen & Phillips, 2003). This biological process is normally in equilibrium and therefore skeletal muscle mass remains relatively constant unless there is a stimulus for change. Resistance exercise is a potent stimulus which causes not only an increase in protein synthesis but also an increase in protein breakdown (Borsheim, Tipton, Wolfe, & Wolfe, 2002). This elevation of both synthesis and breakdown is evidence that significant “remodelling” of muscle protein occurs as a result of resistance-training (Rasmussen & Phillips, 2003). If the resistance training stimulus is maintained over a sufficient period of time, the constant remodelling of muscle protein generally leads to a visible increase in muscle mass, a phenomenon called hypertrophy. This gain in muscular size is attributed to prolonged anabolism, a state in which the rate of muscle protein synthesis is greater than the rate of muscle protein breakdown (Chesley et al., 1992).
In Weightlifting, there is particular interest in hypertrophy as we generally associate larger muscles with increased strength. Therefore we are also interested in the conditions that contribute to and maintain a state of anabolism. Among the most important of these conditions are the appropriateness of nutrition, the quantity and type of physical activity and the influence of the endocrine system (hormones). In regard to nutrition, muscle protein synthesis requires an availability of amino acids. Any meal containing sufficient protein as a source of amino acids that is consumed within 24 hours of resistance exercise results in a net muscle protein accumulation (Rennie & Tipton, 2000). This is because muscle protein synthesis occurs 1-2 hours into the recovery period postexercise (Booth, Nicholson and Watson, 1982) and remains elevated for up to 24h (Chesley et al, 1992; Biolo et al, 1995).
However, in Weightlifting we have a vested interest in optimising the nutritional status to promote hypertrophy. Furthermore, the tendency for elite Weightlifters to train two sessions per day requires the restoration of worked muscles to occur as quickly as possible. It is conceivable that the increased frequency of training may have a negative effect on anabolism and muscle hypertrophy unless there is adequate recovery (Chesley et al, 1992). Therefore it is greatly important that due consideration is given to nutrition, not only in composition but also timing, to optimise the availability of amino acids for protein synthesis.
There is ample evidence that protein should be consumed together with carbohydrate to promote anabolism (Rennie & Tipton, 2000; Rasmussen & Phillips, 2003). The rationale for the consumption of protein and carbohydrate together is provided by Figure 1.
amino acids play a role in providing energy for metabolism and at rest amino acids may contribute 30% of the body’s need for glucose. Therefore not all amino acids are available for protein synthesis. However, the effect of the carbohydrate ingestion and insulin secretion is that more carbohydrate is used for energy metabolism and less amino acids. Therefore the ingestion of carbohydrate has a protein sparing effect and the overall effect of protein and carbohydrate ingestion on anabolism is larger than if protein is consumed alone (Rennie & Tipton, 2000; Rasmussen & Phillips, 2003). There are various recommendations with regard to the quantities of protein and carbohydrate to be ingested after training. One study found that a bolus of 6g of essential amino acids with 35g of carbohydrate after resistance training increased muscle protein synthesis by 350% (Rasmussen et al., 2000). On the otherhand, a study by Tipton and colleagues (1999) recommended a large amount of amino acids (30g-40g) after exercise for stimulation of muscle protein synthesis.
The optimal time for ingesting food sources of amino acids (i.e. protein) to maximise the effects of protein synthesis has been studied. A study by Tipton and colleagues (2001) provided evidence that the ingestion of amino acid/carbohydrate immediately before or immediately after resistance exercise beneficially effects muscle protein synthesis. However, in this study it was concluded that immediately before was better than immediately after. Other studies support the notion that 1-3 hours after exercise is a key window for the ingestion of amino acid/carbohydrate (Rasmussen et al., 2000; Rasmussen & Phillips, 2003). This nutrition window may be explained by MacDougall and colleagues (1999) that muscle protein synthesis peaks around 2-4 hours after resistance training.
It is also useful to have an understanding of the hormonal response to training. Resistance training stimulates the release of various hormones that have an anabolic effect, particularly Growth Hormone and Testosterone (Kramer et al. 1990; Hansen et al., 2001). This hormonal response is an aspect of the body’s homeostatic mechanisms that promote adaptation to environmental stimuli and thereby our survival. Furthermore, feeding before and after resistance exercise alters the hormonal response (Kraemer et al. 2006) and increases muscle protein synthesis (Rasmussen and Phillips, 2003).
The nature versus nurture argument is prevalent in sport. In Weightlifting, elite athletes are often considered to have a genetic predisposition for speed and strength. However there is no conclusive evidence of this.
Coaches and athletes in Weightlifting are understandably interested in the anatomy and function of muscle tissue. Our greatest desire is that such knowledge will enable us to improve our training methodology and explain why it is that individuals differ so considerably in athletic ability. In our search for knowledge, it is inevitable that we will question, at some time or other, how the world’s best athletes in Weightlifting can develop such incredible strength and power. Is it that such athletes are simply freaks of nature possessing a composition of muscle tissue that is significantly different to the ordinary man in the street? Or is it that such athletic prowess is merely the product of an exceptional training environment? Many people believe that high performance in sport requires both factors, a genetic predisposition and an extent of training that exhausts every possibility to nurture the athlete’s talent. This nature versus nurture paradigm is a constant source of argument and debate and has stimulated a great deal of research.
For the spectator watching the Olympic 100m final, genetic predisposition seems perfectly obvious. Not since 1980 has an athlete of Caucasian ethnicity won this event, and indeed the overwhelming majority of finalists have African ancestry. Nowadays we also witness a great deal of success in Weightlifting among Asian nations, particularly the Chinese, and for many people this adds weight to beliefs about the role played by genetic factors in sporting success. But in science, the topic is not at all settled. For example, the importance of genetic factors in determining muscle strength has been gauged by researchers to range anywhere from 0% to 97% (Huygens et al., 2004).
Nevertheless, there is general support for the notion that genetic factors do play a major role in determining success in sport at the highest level. As an example, more than a billion people of European ancestry have inherited a complete deficiency of the protein α-actinin-3 which forms part of the contractile apparatus in muscle cells (MacArthur & North, 2007). The deficiency of this protein has been associated with the inhibition of fast twitch muscle fibre which would seem particularly unhelpful in power sports such as Weightlifting. However, studies involving athletes in Australia and Finland have found that it is exceptionally rare for elite level power athletes to have a deficiency of α-actinin-3 (North et al, 1999; MacArthur & North, 2007). Thus a degree of ‘genetic good luck’ is in play.
One of the most widely held beliefs is that the world’s best Weightlifters must possess a higher proportion of fast twitch muscle fibre. Before taking a look at whether this proposition might be true, some explanation of the difference between slow twitch and fast twitch muscle fibre is needed at this point.
One of the earliest papers that summarised the differences between fast and slow twitch muscle fibres, and used the terminology “Type I/Type II”, was published in 1960 by Dubowitcz and Pearse. In the more than 50 years since, it has been generally accepted that there are three (3) distinct muscle fibre types as summarised by Table 1.
Table 1: Types of Muscle Fibre
Adapted from MacIntosh, Gardner, McComes: Skeletal Muscle: Form and Function
Type I fibres produce less contractile force than Type II but are much more resistant to fatigue and therefore play a more prominent role in endurance activity. The greater fatigue resistance of Type I fibres is due to a high capacity to utilise the oxidative (aeroboic) energy pathway.
It should be noted that the classification of muscle fibres in the literature often confusingly refers to the subdivision of Type II fibres into Type IIa and Type IIb (as opposed to Type IIa and Type IIx). This confusion arises from the two different methods for testing for fibre type. In general however, Type IIx is preferred rather than Type IIb. Furthermore, the literature often refers to “hybrids” of these basic types. Such hybrids may exist as a result of imperfect classification techniques, or as a manifestation of cellular transformation from one fibre type to another (Schroeder, Rosser & Kim, 2014) or simply the various stages of degeneration/regeneration of muscle tissue.
In Weightlifting, it is a popular belief that champions must be genetically endowed with a higher proportion of Type II (fast twitch) muscle fibre as opposed to Type 1 (slow twitch). A study by Fry and colleagues (2003) examined and compared muscle biopsies (vastus lateralis) of male USA Weightlifters who had qualified for national championships with untrained male college students. Their finding was that the distribution of Type I /Type II muscle fibres among elite Weightlifters was similar to untrained persons. It is questionable therefore that the genetic gift of the Weightlifter is that they are born with a higher proportion of Type II (Fast Twitch) muscles fibres. What is clearly evident, however, is that there are significant differences between power and endurance athletes in the Type I/Type II distribution ratio (see Table 2). Therefore it can be said that Weightlifters will have a higher proportion of Type II (fast twitch) muscle fibres than endurance athletes.
Table 2: Muscle Fibre Type Distribution in Vastus Lateralis
Type I and hybrids
Type IIa, IIx and hybrids
Terzis et al. (2010)
Fry et al. (2003)
Costill et al. (1976)
Wilmore, Costill & Kenney (2008)
Long Distance Runners
Tesch & Karlsson (1985)
Jansson & Kaijser (1977)
Fry et al. (2003)
Wilmore, Costill & Kenney (2008)
While the proportion of Type II fibres in Weightlifters may not significantly differ from untrained individuals, there have been consistent findings of a decrease in Type IIx fibres and a corresponding increase in Type IIa fibres in individuals who engage in resistance training (Hather, Baldwin and Dudley, 1993; Williamson et al., 1991; Carroll et al., 1998; Williamson et al, 2001; Fry et al., 2003; Goruljov & Rumjanceva cited in Smrkolj & Škof, 2013;). It is controversial to say that resistance training causes Type IIx fibres to convert to Type IIa but this altered ratio of Type IIa/Type IIx muscle fibres occurs in individuals irrespective of the nature of weight-training (Adam et al., 1993). Furthermore, “interconversions” between type IIa and IIx are well recognised in the literature (Smrkolj & Škof, 2013).
In addition, to an increase in proportion of Type IIa muscle fibres, the literature also recognises that there is a significant increase in their cross-sectional area, or hypertrophy of individual muscle fibres. This increase in cross-sectional area could be explained by an
Table 3: Cross-sectional area (μM2)
Source: Fry et al. (2003)
increase in the contractile proteins, sarcoplasm, connective tissue or a combination of all of these (Wilmore, Costill & Kenney, 2008). Table 3 compares the cross-sectional area of muscle fibres in Weightlifters and untrained individuals and interestingly Type IIB (Type IIx) fibres are significantly smaller in size in Weightlifters than untrained individuals.
The notion that Weightlifting training increases the size and proportion of Type IIa fibres (medium twitch force, fatigue resistant) at the expense of Type IIx fibres (high twitch force, highly fatigable) seems counter-intuitive in the case of Weightlifters and raises many questions. It is the very nature of the sport of Weightlifting that athletes should specialise in one-off maximal force contractions. Therefore why does the higher contractile force Type IIx fibre become practically non-existent? This question has no definitive answer at the moment but there are theories. One theory is that the transformation from IIx to IIa fibres might be due to requirement for Weightlifters to focus on power production rather than absolute strength, and that Type IIa fibres have more force development capability (Carroll et al., 1998). Another theory is that Type IIa may have a lower activation threshold which may be important in the recruitment of muscle fibres (Henneman cited in Carroll et al., 1998).
But one possible answer seems yet to be tested. If Type IIa fibres are more fatigue resistant is the Weightlifter’s preoccupation with sets of multiple repetitions to blame? Much of the training of Weightlifters focuses on sets of 3 repetitions and at various times of the year 5 repetitions on exercises such as squats is not uncommon. On the otherhand, single efforts at the highest intensities are a very small proportion of overall training.
Lastly, experiments have clearly demonstrated that muscle fibres change in characteristics when innervated by a different motor neuron. If a motor nerve to a fast twitch muscle fibre is transplanted to a slow twitch muscle fibre, the muscle fibre is transformed and takes on characteristics of a fast twitch muscle fibre. Similarly, a fast twitch muscle fibre will transform to a slow twitch muscle fibre if a motor nerve is transplanted that was formerly connected to a slow twitch muscle fibre (Buller, Eccles & Eccles, 1960). These transformations show strong evidence of the nervous system as a controlling agent of muscle contraction.
The split squat is an excellent exercise for assisting beginners to learn the correct receiving position for the Jerk. However, the exercise must be performed in a manner that is specific to weightlifting.
From an initial standing position with feet hip width apart, the athlete takes a long step forward (see “Learning Progression” below to determine which leg should go forwards).
In this position, feet split from front to back, the athlete must fix the shin of the leading leg so that it is completely vertical. This is one of the key coaching points of this exercise. Coaches should actively prevent the knee from going forwards from the vertical plane using their hand if necessary. The athlete must learn how it feels to maintain the front shin totally vertical throughout the exercise.
The rear foot position must be closely watched by the coach or others. The heel should be well raised from the floor throughout. Furthermore the foot should be straight and remain completely stable i.e. the heel does not lower to the ground.
This exercise is very much about training the rear leg. The object is for the athlete to learn to bend, and keep bent, their rear leg in the receiving position for the jerk. This has a major effect on the athlete’s ability to keep a neutral spine during the jerk (see “Rationale for Exercise” below).
What the beginner must develop
The split squat exercise assists the athlete to learn to:
Accept a degree of bend in the knee of back leg in the split receiving position
Strengthen the back leg to maintain a degree of bend in the knee
Strengthen postural muscles to keep a neutral pelvis
Keep the front shin vertical in the split receiving position
Attain an even distribution of weight on both feet
Rationale for Exercise
It is unfortunately common to see weightlifters with significant deficiencies in the jerk receiving position. The Jerk receiving position is not easily mastered and for many, problems tend to be ongoing throughout the lifting career.
Of particular concern, athletes can easily acquire a “straight back leg” receiving position and, as a result, a problematic tilt of the pelvis caused by tight hip flexors. This pelvic tilt is problematic because it increases the lordotic curve of the lumber region of the spine. Any abnormal curvature of the spine increases the risk of injury.
Moreover, the “straight back leg” receiving position in the jerk is often accompanied by a forward lean of the trunk and a greatly uneven distribution of weight on the feet. As a result, the athlete will suffer instability as the weight will move towards the front of the base and will likely continue moving forward. In Figure 2 above right, the stripes on the athlete’s uniform provide an excellent guide to the degree of pelvic tilt, and lumber curvature. You can see that there is a significant change in angle between the upper and lower torso.
Important muscle and flexibility development
The issue for weightlifters in the jerk receiving position is that the movement backwards of the rear leg causes a rotation of the pelvis forwards. This rotation can be minimised by increasingly flexibility of hip flexors (ilio-psoas, pectineus, rectus femoris and others) and strengthening abdominals (see Figure 3).
Beginners need to determine which foot goes forward and which foot goes backwards in the split position. Methods to determine this question include:
Athlete determines – the athlete is encouraged to try both ways and see which way feels right to them
Coach determines – the coach asks the athlete to try both ways and makes an assessment of which way looks to provide best position for the athlete
Coach endeavours to assess which foot ‘naturally’ goes forward by asking the lifter to jump into a split position without consciously making a decision about which foot goes forward.
Coach endeavours to assess which foot ‘naturally’ goes forward by giving the athlete a push in the back and seeing which leg they step forward to steady themselves.
Every coach has his/her own way of determining the ‘natural foot’ but consideration should be given to the argument that it is the rear leg that needs to be strongest. The rear leg has the most difficult position to attain.
After a beginner has experienced a good measure of success with the Split Squat, the next progression could be the Jerk Balance exercise.
Split squats, in Weightlifting, are mostly used for teaching skill or for remedial purposes i.e. correcting issues in the jerk receiving position.
This exercise should form part of the initial training regimen of the beginner and therefore it does not make sense to set the training intensity of this exercise as a percentage of 1RM. Instead, weights should be strictly limited to enable the beginner to focus on achieving excellence of position.
Generally this exercise is performed in sets of 5 repetitions, and a volume of 5-6 sets performed once or twice per week is as much time as can be afforded for beginners or persons with a problematic receiving position for the jerk.
This article focuses on Jerk technique, the second part of the competition movement known as the Clean and Jerk. In particular, the article discusses the conventional technique of the ‘Split Jerk’ which is employed by the vast majority of Weightlifters worldwide. While the author acknowledges that World Champions have used the ‘Power Jerk’ or ‘Squat Jerk’ techniques, the Split Jerk technique is recommended as the most effective and the safest.
From this point on, the Split Jerk technique will be referred to simply as “The Jerk”
Key Issues of Jerk Technique
The Jerk is a highly complex movement that many athletes in Weightlifting find harder to master than the Snatch. In the Jerk, athletes must overcome several key issues if they are to become good exponents of the lift. These key issues are:
The extreme heaviness of the barbell. Although Weightlifters are masters of ‘heaviness’, an exceptional performer in the Clean and Jerk will lift in excess of 80% of their best Back Squat. In addition to excellence of Jerk technique, the athlete will need great courage, will power and tenacity to complete a Clean and Jerk that is near to the limit of their strength capacity.
Achieving and maintaining a lockout of the elbows with the weight overhead. If an athlete, for anatomical reasons, has a difficulty in maintaining an elbow lockout, then the likelihood of reduced performance potential in the Jerk increases significantly.
Even when both elbows are locked out, the athlete will experience significant difficulty in maintaining balance and control of the weight overhead. This is a matter of physics. In the situation where the athlete has a barbell of twice bodyweight overhead, the combined centre of mass (of the barbell and lifter) will be situated at approximately neck height or higher (see figure 2 below). The higher the combined centre of mass, the greater the balance problem.
The Jerk is a movement that is unforgiving of any weakness in the position of the body in the receiving position. An athlete may elevate the bar high enough, and have sufficient lockout strength in the arms, but if the rest of the body is not positioned correctly to support the bar, then the lift is likely to be lost. A common receiving position error as depicted by Figure 3 below, shows the weight of the bar toward the front of the base with hips are behind the bar and a pronounced forward lean of the torso. These factors tend to cause the athlete to have significant difficulty in maintaining stability of the bar overhead.
The receiving position as shown by Figure 3 above is very likely to result in forward movement of the bar as the athlete struggles with the receiving position. This error of Jerk technique occurs not only because the weight is distributed toward the front of the base of support, but also because there will be an uneven amount of force emanating from both legs. The ideal situation as depicted by Figure 4 below, is a weight distribution over the centre of the base, and equal amount of force derived from each leg, and an equal amount of pressure through each foot.
Another all too common issue in the Jerk is Pelvic Rotation as depicted in Figure 5 below. Rotation of the Pelvis in a forward direction results in a hyper-extension of the lumbar spine, or Lordosis. Under heavy load (with a barbell overhead), it is ideal for the spinal shape to remain normal. Any adverse or exaggerated curvature of the spine increases the risk of injury. The cause of such pelvic rotation in the Jerk can be: (1) As a result of errors in the learning process for the Jerk Receiving position and/or (2) Tightness in hip flexors. These issues are described later in this article.
Learning Jerk Technique
It is important to take a long-term approach, from the very first moment that training begins, toward achieving total confidence and positional correctness in Jerk technique. Coaches should understand that the skill learning process should not be rushed. Errors that accumulate early in the learning process are hard to correct later. It is unfortunate that beginning athletes can often succeed with Jerks despite poor technique but as the athlete progresses to higher levels of qualification, the special issues described above will undoubtedly diminish the athlete’s performance potential unless appropriate attention is given to the following key learning objectives:
A smooth and purposeful ‘dip and drive’
Rapid and efficient movement under the bar
Positional correctness of the body in the receiving position
Controlled recovery to the finish position
The Dip Phase of the Jerk
Not all aspects of the Dip and Drive are well understood. Easy to understand, but not easily achieved, is the need to elevate the bar in one direction only – vertically upwards. This directional control requires an absolute avoidance of any rotation of the upper body during the dip, in other words the body must stay totally vertical as displayed in Figure 5. It is critical for the athlete to ‘bear down’ through the heels in the Dip to prevent forward movement of weight distribution to the front of the foot.
A common fault in the dip is an inability to “dip straight” (keep the torso vertical). This incorrect action, displayed in Figure 6, will send the barbell forwards. Even a slight rotation of the body will have an undesirable effect. Once the barbell is moving forwards it gains momentum and becomes very hard, and often impossible, to stop. In Figure 6 it can also be seen that the forward movement of barbell is so dramatic that even at the bottom of the dip the barbell is no longer over the base of support.
Another common fault in Jerk technique is forward movement of the ‘centre of pressure’ during the dip. The ‘centre of pressure’ is the effective point of application of force through the foot into the floor. Figure 7 portrays the common fault where the athlete starts the dip with the centre of pressure toward the heel but as the bottom of the dip is reached, the centre of pressure has moved forwards to the ball of the foot. The probable effect of this is forward movement of the body during the dip and as a consequence the bar gains forward momentum. This issue is also the root cause of the problem depicted in Figure 6 above.
Other aspects of the Dip and Drive for the Jerk are not well understood. In particular, the velocity of the dip is critical to success. The higher the downward velocity of the bar, the greater ‘impact’ of the bar at the bottom of the dip. The impact, that is the abrupt stopping of the bar and changing its direction to upwards, must be absorbed by the body. The effect of this impact can be seen in slow-motion video and is typically manifest in the ‘buckling’ (loss of rigidity) of the torso, that is bending of the spine, dropping of elbows and partial collapse of chest. On the other hand, there are also beneficial effects of absorbing the kinetic energy of the barbell in the dip. To some extent, the body acts like a spring and the ‘recoil’ is the upward movement of the bar (The Drive). Therefore, if the velocity of the dip is too slow, the athlete looses some of the beneficial spring effect. Furthermore, there is also the complicated issue of the spring in the bar, which increases in magnitude the greater the weight. It is important to control the dip velocity. If it is too rapid or too slow, there can negative consequences.
In Figure 8 below, X is the start of the Dip and Z is the bottom of the Dip. Y is an arbitrary point at which barbell downward velocity begins to slow. The distance between X and Y (marked in Figure 8 as the distance d1) is the “fall” distance. This is not a free fall as the athlete is resisting the downward movement of the bar. However during the “fall”, the bar will be accelerating. The distance between Y and Z (marked in Figure 8 as d2) is the “impact” distance and is characterised by deceleration of the bar until it comes to a stop at Z. During the “impact” distance, the athlete is exerting great force to decelerate the barbell to zero and change its direction to upward.
The following spreadsheet illustrates that the consequence of a more rapid dip during the fall distance (in the Jerk) is that more force is required to decelerate and change the direction of the bar. The difference between Case 1 and Case 2, is that in Case 2 the fall time is 0.25 sec or 25% longer duration than Case 1 which is 0.20 sec. Therefore the downward velocity over the “fall distance” is faster in Case 1 (1.18 m/sec) than in Case 2 (0.944 m/sec). The result of the slow dip speed in Case 2, is that force required to turn the bar around is 717 Newtons, and this is significantly less than the force required in Case 1 (897 Newtons).
There may be a limit to which each athlete can produce sufficient force at the bottom of the Dip without significant “buckling” of the body. The issue is that coaches and athletes are not aware that a fast Dip can be problematic. The incorrect assumption made is that a faster Dip stores more kinetic energy, and therefore a more ballistic Dip and Drive gives the athlete a better chance of elevating the bar to the height needed. However this assumption does not take account of the athlete’s limited ability to avoid “buckling” which causes the kinetic energy to be absorbed in body position changes rather than transmitted to the barbell.
Jerk Receiving Position with Straight Back Leg
It is unfortunately common to see weightlifters with significant deficiencies in the Jerk receiving position. The Jerk receiving position is not easily mastered and for many, problems tend to be ongoing throughout the lifting career.
Of particular concern, athletes can easily acquire a “straight back leg” receiving position (see illustration on right) and, as a result, a problematic tilt of the pelvis caused by tight hip flexors. This pelvic tilt (illustrated and explained above) is problematic because it increases the lordotic curve of the lumber region of the spine. Any abnormal curvature of the spine increases the risk of injury.
Moreover, the “straight back leg” receiving position in the Jerk is often accompanied by a forward lean of the trunk and a greatly uneven distribution of weight on the feet. As a result, the athlete will suffer instability as the weight will move towards the front of the base and will likely continue moving forward. In the above illustration the stripes on the athlete’s uniform provide an excellent guide to the degree of pelvic tilt, and lumber curvature. You can see that there is a significant change in angle between the upper and lower torso.
The concept of neural adaptation is fundamentally important knowledge that helps us understand the process by which the Weightlifter develops skill, power, strength, speed and coordination. For example, the concept helps the Weightlifting coach to understand why:
An increase in strength is initially achieved without any measurable increase in muscle hypertrophy
Beginners display inhibition and awkwardness of movement in the initial stages of learning Weightlifting skill
The training of Weightlifters must be predominantly high in intensity i.e. over 80%.
Athletes with extensive experience in weight-training often have significant difficulties in learning Weightlifting movements
Resistance training to develop greater strength within a muscle group will simultaneously develop strength within muscles that oppose the contraction of the trained muscle group.
Ex-athletes retain the ability to lift far more than untrained or novice individuals long after they have ceased training.
The Motor Unit
When an individual begins Weightlifting, strength is gained rapidly without any measurable hypertrophy of muscle tissue. This is evidence that the development of muscular strength is a function not only of adaptation within muscle tissue itself but also the nervous system that innervates muscles to contract (Gabriel, Kamen & Frost, 2006). This adaptation of the nervous system is referred to as neural adaptation and includes several possible mechanisms that contribute to strength development. In order to understand these mechanisms, it is beneficial to have a basic knowledge of the structure known as the ‘motor unit’ (See Figure 2). A motor unit consists of a motor nerve cell (motor neuron) situated in the spinal column, the motor nerve fibre, the motor end-plate or junction between the nerve fibre and the muscle, and the colony of muscle fibres innervated by the motor neuron (Reilly, Secher, Snell, & Williams, 1990). A motor unit is thought to have a specific threshold for stimulation. If the electrical signal from the motor neuron via the nerve fibre is sufficiently strong (greater than the threshold) all muscle fibres which are part of the motor unit will contract. If a pulse is received that is less than the threshold, then the motor unit will not be ‘fired’, i.e. there will be no contraction by any muscle fibre in the motor unit. This is often referred to as the all or none principle (all muscle fibres in the motor unit will fire or none will).
The strength of a muscle contraction will in part be determined by a combination of any or all of the following:
The total number of motor units which can be activated (fired) at any one time
The frequency of electrical stimulation pulses received by the motor unit
The synchronisation of motor unit firing
Greater efficiency at the neuromuscular junction (motor end plate)
Neuroplasticity or enhancement of the motor cortex area of the brain
Possible reduced inhibition of agonist muscle contraction (unconfirmed by research)
For a more in depth understanding of these factors read Neural Adaptation by Gabriel, Kamen and Frost (2006).
For the Weightlifting coach a detailed knowledge of these mechanisms is not necessary. Instead, it is more important to consider the overall importance of neural adaptation to the improvement of athletic performance. The development of strength is much more complex than mere hypertrophy and it is useful to discuss how an understanding of the concept of neural adaptation helps the coach to optimise the training of the Weightlifter.
Traditionally in Weightlifting, much of our thinking about training focusses on the observable physical changes that take place within the musculature when in reality the most profound changes take place within the nervous system. In particular, in recent decades science and medicine have made great advances in understanding ‘Neuroplasticity’ and how the brain adapts to stimuli within the environment. Learning the movement patterns of Weightlifting presents very strong stimuli that cause adaptation in the brain and nervous system. The problem for the brain, particularly when learning a new movement that is complex and involves high intensity muscular contraction, is to activate (or not activate) motor units within muscle groups to cause and control very precise movement of the body. In performing the complex skills of Weightlifting, flexion and extension within multiple joints must be coordinated, and the resultant movement must fall with a tolerance range that allows the achievement of the lift. In Weightlifting, the contractile force developed by muscle tissue is well beyond the norm for everyday life and therefore part of the brain’s adaptation is not only to precisely coordinate movement within multiple joints but also to stimulate muscle tissue to contract more forcibly than previously experienced.
The training of the Weightlifter must take account of the need for neural adaptation that enables the athlete to acquire the ability to produce rapid and forceful contraction of muscle tissue in a highly sophisticated and coordinated way. Since now, we have some understanding that strength is not purely a matter of muscle size but relies heavily on neural adaptation and the excitation of motor units, it is important to ask questions about the specific type of training needed for Weightlifting.
Since the 1970’s, the authors of Weightlifting texts have put forward the notion that strength training is best engendered by training 5-6 reps per set to promote hypertrophy.
The advanced lifter and in particular those striving to increase muscle mass, lift the bar 5-6 times in a set. A great number of repetitions of an exercise during one set is used for providing the excessive load for one and the same group of muscles to evoke stress reaction and obtain the strength increase (Falameev, n.d.).
On the basis of a training analysis of top USSR lifters, we conclude that lifters whose bodyweight is at the top (or even above) of their weight class should, as a rule, use sets of 2-3 reps. But since strength training is more effective if growth of structural protein occurs, we advocate episodic use of 4-6 rep sets as being most favourable for muscle trophicity (Vorobiev, 1978).
Both Falameev and Vorobiev were distinguished Russian athletes who went on to become coaches during the years when the USSR was dominant in world Weightlifting.
The relationship between strength and cross-sectional area of muscle is well understood (Fukunaga et al, 2001) thus training for hypertrophy is an important objective. However, at best an athlete can achieve 80-85% of 1RM by performing sets of 5-6 reps and although the effort of the individual is intense, it is arguable that a different form of neural adaptation is required for performance improvement in Weightlifting.
A different approach to performance improvement in Weightlifting was taken by Ivan Abadjiev, head coach of the Bulgarian Weightlifting team, that astonished the world of Weightlifting in the 1970’s. The approach relied on single rep sets up to planned or expected maximum efforts on a daily basis not only the classical movements of the snatch and the clean & jerk but also squats (Garhammer & Takano, p511). In more recent times, Sivokhin and colleagues (2012) stated no more than 1-2 repetitions per set were used in the training of the Kazahkstan Weighlifting Team in pursuit of the goal of selective hypertrophy of fast twitch muscle fibres. Support for this approach is based on the need for a sufficiently high training load to maximally recruit muscle fibres and produce the required neural adaptation (Hakkinen, 1985; Gonzalez-Badillo, Izquierdo & Gorostiaga, 2006). Furthermore, in Australia, Jones and Keelan (2005) recommend that strength training is advanced by training 1-2 reps per set at very high intensity (90-100+%) and at such a level of intensity, it is not possible to achieve 5-6 reps per set.
In the Weightlifting world there is much uncertainty about the best methodology to develop strength. It is still commonplace to see athletes pursuing strength development with high volume training utilising 5-6 reps per set particularly during the ‘preparatory phase’ of a periodised training program. Certainly athletes do gain in hypertrophy and advance their 5RM result of such training but a reliance on 5-6 reps per set for strength training in the lead up to an important competition is not congruent with neural adaptation theory. The lifting of maximal or near-maximal weights (high intensity training) is fundamentally necessary to stimulate the required neural adaptation. Maximising strength, power and hypertrophy may only be accomplished when the maximal numbers of motor units are recruited. Thus heavy loading in experienced individuals is needed to recruit high-threshold motor units that may not be activated during light to moderate lifting (Kraemer & Ratmess, 2004).
However, there is strong support for the notion that high-intensity (90%+) training with low rep sets (1-2) cannot be performed all year round. Among the negative influences of an over focus on 1 or 2 heavy or maximal efforts per set is a risk of encountering a training plateau (Kraemer & Ratmess, 2004), and a worsening of technique and emotional state (Orlov, 2015). For these reasons, a typical Weightlifting program takes a periodised approach that includes a preparatory phase and a competition phase. The preparatory phase provides some relief from continual high-intensity effort but during this phase athletes can still be challenged by pursuing personal bests for higher repetition sets for strength training.
In typical high-volume (preparatory) phases for weightlifters contain more training sessions per week (6-15), more exercises per session (3-6) and more repetitions per set (4-6).Typical high-intensity (competition) phases for Weightlifters contain fewer training sessions per week (5-12), fewer sets per exercise (3-5), and fewer repetitions per set (1-3) (Garhammer & Takano, p508).
Inhibition of Movement
Neural adaptation also helps us to understand the transformation of beginners in Weightlifting. Initially movements of the beginner appear inhibited, restricted and uncoordinated and, in general, we attribute this to lack of skill. However, this inhibition of movement can also be explained as a mechanism to prevent injury, or more especially to protect joint integrity (Gabriel, Kamen & Frost, 2006). When a motor task is unfamiliar, the central nervous system has to deal with the need not only to produce force through muscle contraction but also to limit the force produced as a measure of self-preservation. Logically, for the beginner, self-preservation is a higher order need than maximal performance and the inhibition of movement begins to dissipate only after considerable skill learning and neural adaptation.
The question of whether neural adaptation through strength training also involves a reduction in antagonist action has been investigated. As has been discussed in pages 8-9, when a muscle contracts to cause movement there is also a co-activation in the antagonist muscle. Thus, the force produced in an agonist muscle must not only overcome the weight to be lifted but also the opposing force developed in the antagonist muscles. A study by Carolan and Cafarelli (1992) found a 11.5 – 14.9% reduction in Biceps Femoris (BF) activity as a result of isometric training of knee extensor muscles. The BF activity was measured using a non-invasive technique in which electrodes are placed on the skin overlying a muscle to detect the electrical activity of the muscle (MedicineNet.com, 2015). However a study by Gabriel and Kroll (1991) contradicts the notion that the training process reduces antagonist muscle activity. In their study, Gabriel and Kroll found that however people engage in strength training there is an increase in antagonist activity. So, according to this finding, no matter how much your quadriceps develop in strength as a result of performing squats, there would be an increase in antagonist action of the hamstrings even when performing maximal attempts. To some extent this is logical, but the Gabriel and Kroll study does not rule out that there is a beneficial change in the ratio of agonist to antagonist activity.
The inhibition of movement as a result of the co-activation of antagonists may not seem knowledge that is overtly useful to the Weightlifting coach. However, such knowledge may explain some common technical issues and lead to the development of remedial strategies. As an example, athletes who move into weightlifting after extensive training of the biceps generally have difficulty in attaining and maintaining a strong lockout in the jerk. In such a circumstance, the biceps are co-activated as the triceps perform the work to extend and lockout the arm at the elbow joint. When the biceps have been well-developed, their opposing force to the extension of the elbow by the triceps is very strong. It takes time and persistence to detrain the biceps and retrain the musculature of the arm and shoulders to attain the coordination and balance of forces required to sustain a good lockout. This situation is made worse when athletes have also engaged in extensive bench press training, as this also creates strong antagonist action from the pectoral muscles. As stated on page 10 (Figure 1), co-activation of the hamstrings during the pull or the squat creates force that opposes the work performed by the quadriceps.
Neural adaptation is therefore a topic of importance to the weightlifting coach which helps to better understand training methodology and deal with common technical issues. An insight into neural adaptation enables a better understanding of strength, skill learning, muscle fibre recruitment, muscle fibre transformation, training intensity, technical issues, co-activation and inhibition of movement. How we perform in sport is very much about the ‘intelligence’ we can create within our nervous system rather than a genetic pre-disposition of muscle fibres as many believe.
The human body has numerous regulatory mechanisms that exert control of its internal environment to promote survival. If the fluid content of the body diminishes, we feel thirsty and drink more. If the core temperature of the body rises, we are stimulated to take measures to cool ourselves down and return our core temperature to normal. If our blood sugar level falls, we begin to feel hungry and our motivation to eat is increased. These examples provide a basic understanding of homeostasis, the tendency for all living organisms to regulate internal conditions.
The internal environment of the body is subjected to stress when we exercise, and the greater the intensity of the exercise the harder the homeostatic systems have to work. There are visible signs of these mechanisms at work when we exercise but a great deal more is not visible and not easy to understand. As coaches and athletes, we rely therefore on scant knowledge of unseen homeostatic processes and as a result it is difficult to set training programs that deliver an optimal level of stress.
If exercise stress is frequent, systematic and consistent in nature, as when we engage in a well-designed and purposeful training program, the body’s homeostatic mechanisms promote adaptation to the stress experienced. Indeed, this adaptation is the objective of the training process and therefore in devising a training program we must have in mind the specific nature of the adaptation desired. However, if the exercise stress is infrequent, inappropriate or unsystematic in nature then the performance gain we seek may not occur or occur more slowly than we would like, or even a loss of performance occurs (a process referred to as maladaptation).
In Olympic Weightlifting, the end goal of adaptation process is that athletes will develop an exceptional ability to:
Apply force to a barbell in a very specific manner to cause sufficient vertical displacement (height from the ground),
Move with exceptional speed under the bar, and
Adopt a body position that prevents the bar from falling back to the ground and to the satisfaction of the referees.
The adaptation needed to develop the above abilities is physiologic and psychological in nature and it should be borne in mind that the brain is at the centre of this adaptation process. It should be appreciated that all movement occurs as a result of activity within the neurons of the central and peripheral nervous system. Therefore, adaptation to the stresses induced by sport training should be viewed as a holistic process and that a focus on strength as purely a physiologic phenomenon is an error.
The achievement of excellence requires an athlete to be in an optimal state of physiologic and psychological readiness, and assisting athletes to obtain this goal is the art and science of coaching. Weightlifting coaches, particularly those who work with high performance athletes, have a need to make frequent, if not daily, decisions about an athlete’s training load. However, it is most unlikely that such decisions, even among experienced coaches, are without some degree of error. It is very difficult for a coach to determine in advance whether a particular training load will be adaptive or maladaptive and at what point maladaption begins as a result of chronic training overload (Kenttä & Hassmén, 1998).
Therefore, the accumulation of knowledge of how the body adapts to exercise is an important asset in determining training load and helps to minimise errors that lead to injury and overtraining. It is useful therefore to have an appreciation of:
Changes in bone density
Muscle anabolism and hypertrophy
Muscle fibre composition and interconversion
Endocrine response to training
The high intensity exercise experienced in Weightlifting training stresses the internal environment of the body and as a result of homeostatic mechanisms there is stimulus for adaptive change.