Manually Applied Eccentric Training For Athletes: Pain vs Gain?
Eccentric only exercises are becoming frequently more popular within strength and conditioning. These are often applied for prehabilitation purposes[1][2] or to reflect specific demands within certain sports such as eccentric hamstring work for sprinters [3]. This article is going to focus on how to incorporate eccentric training as a method for increasing hypertrophy in athletes. This is also applicable to practitioners working with the general population where I believe this practice is widely underutilised. We will focus on how manually applied eccentric exercises can be used to add a greater growth stimulus to certain muscle groups and how I might incorporate this into my own programs. I will also give some practical examples towards the bottom of the document. The following subtitles will be covered:
1. Eccentric Contractions
2. Training for Hypertrophy
3. Eccentric Training for Hypertrophy
4.. Benefits of Manually applied Eccentric Training.
5.. Weaknesses of Manually applied Eccentric Training.
6. Practical Applications and Recommendations
7. Conclusion
Eccentric Contractions
Eccentric muscle actions occur whilst a muscle is lengthening. Most commonly performed gym exercises include a concentric isometric and eccentric portion. For example in the bicep curl the concentric portion would be lifting the weight upwards towards the shoulder whereas the lowering portion would be lowering the weight down. Elbow extension occurs during the eccentric contraction of the biceps and can be distinguished from elbow extension via concentric contraction of the triceps (see Fig 1).
Fig 1) a)i) Starting position to the movement ii) Concentric contraction of the biceps during elbow flexion iii) Isometric contraction of the biceps iv) Eccentric contraction of the biceps during elbow extension.
i) ii) iii) iv)
Fig 1b) Concentric Action of the Triceps during elbow extension.
Training for Hypertrophy
Hypertrophy can be useful in many sports due to its strong correlation with strength[4] and due to the accompanying increase in body mass, which may be helpful in certain sports. The main mechanisms that have been suggested to lead to hypertrophy include mechanical tension and metabolic stress (although much of this has been associated with occlusion type training[5][6][7]). There are also various methods by which muscle damage could influence hypertrophy[8]. Although many of these present sound theoretical rationale for hypertrophy, a direct study is yet to show that greater EIMD (Exercise Induced Muscle Damage) leads to greater hypertrophy[9][10]. These studies are difficult to interpret however as none have been performed on trained subjects and therefore sufficient overload may be achieved with a minimal stimulus. Outside of these factors hypertrophy is often associated with greater training volumes and intensities[11]. These variables are therefore also important training considerations for hypertrophy.
Eccentric Training for Hypertrophy
Eccentric training has frequently been shown to lead to higher levels of hypertrophy than traditional resistance training through varying different modalities.[12][13][14]
Leading expert in this area Jonathan Mike recommends incorporating the following eccentric training strategies:
The 2/1 Technique
The Two Movement Technique
Enhanced Eccentric Duration
Supramaximal Training[15]
This article will focus on using manual resistance which is a variation of supramaximal training which involves manually ‘’forcing’’ the individual to resist external pressure. To find out more about other forms of eccentric exercise click here [16].
Benefits of Manually applied Eccentric Training.
The potential benefits of this type of training are listed below:
Muscle Damage
Various studies have reported that eccentric exercise leads to greater EIMD[17][18] (Exercise Induced Muscle Damage). Whilst this is reported to be a mechanism for hypertrophy it also is often associated with a delayed onset of muscle soreness[19], although the exact relationship between these two variables is still unclear[20]. Nevertheless, eccentric exercise is associated with both EIMD and DOMS[21] when compared to other exercise modalities. This creates various issues which will be discussed later in this article.
Greater Force Production for Lower Energy Cost
During eccentric contractions, we can utilise much greater force than in concentric exercise and for a lower neuromuscular cost[22]. This is thought to occur due to the contribution of various other passive structures within the muscle [23]. Because of this you can work at a much greater intensity than is possible using traditional resistance training strategies. Due to these factors a higher training volume may be possible compared to concentric muscle actions which may also lead to hypertrophy.
Isonertial Component
When using, manual eccentric exercise the coach can apply resistance throughout the movement and regulate that in response to the strength of the individual or muscle group. For example if we look at a bicep curl the biceps are strongest at approximately 90 degrees of elbow flexion however a traditional curl is generally the most difficult at the bottom of the exercise. This means that a normal bicep curl may not be generating as much tension as is possible. Due to the nature of manual eccentric exercise we can vary the degree of resistance to maintain a high level of tension throughout the movement. Alternatively, we can apply resistance in certain areas to target specific areas of the musculature.
Motor Unit Recruitment
During traditional resistance training motor unit activation follows the size principle[24] this involves the preferential recruitment of low threshold motor units. However certain theorists have suggested that eccentric exercise can preferentially recruit fast twitch motor units[25][26]. The ability to recruit fast twitch motor units is a key neural adaption to resistance training and allows for an increase in force generation in subsequent activities, this would then enable and individual to perform with at a higher intensity during subsequent training sessions. However, weather preferential high threshold recruitment occurs remains controversial and how this might affect subsequent exercise is equally unclear. Despite this it does offer another potential benefit of eccentric exercise.
Weaknesses
As we have established manually applied eccentric training can lead to greater hypertrophic effects through increased muscle damage, increased volume and intensity compared to concentric muscle actions and due to the isonertial nature of manually applied resistance. However there are still various negative’s associated with eccentric training particularly supramaximal training. I will focus on this from the standpoint of working with athletic populations although some of these would apply for any individual.
1. DOMS- As previously discussed, eccentric exercise is known to make you ache considerably more than concentric movements. This can be a large problem particularly when you are working in sport, where athletes must perform to a high level in each individual training session. In my experience this is particularly important to consider when working on the lower body particularly for the hamstrings which are often very prone to fatigue and injuries amongst athletes.
2. Application issues- It takes a reasonable amount of skill to apply manual eccentric muscle actions particularly for certain muscle groups. Because the training is supramaximal athletes will often find compensation strategies to attempt to resist the movement. It is therefore very important that similarly to a normal resistance training program technique is taught and encouraged.
Of course many of these challenges will differ for different individuals so as ever experimenting on how to apply this specifically for your group is recommended.
Practical Applications and Recommendations
It is important to remember that we are looking at applying eccentric exercise for hypertrophy amongst athletes when considering application strategies. Due to this, we must consider the various demands that are placed on an individual through sports training and alternative conditioning requirements. It is for this reason that I would suggest that we proceed with caution when applying this form of manual eccentric training. I have found these most useful when working on accessory exercises which will not make up the bulk of the exercise routine. When doing this, I have found it allows for a time efficient way to get a strong hypertrophy stimulus. I also tend to use these more commonly with the upper body as soreness in this area tends to be much more bearable for the athlete. Examples of exercises of this nature can be seen below:
Example 1-Eccentric Reverse Fly
a) b) c)
Example 2- Eccentric Cable Tricep Extension
a) b) c)
Example 3- Eccentric Incline Flyes
a) b) c)
Example 4- Eccentric Preacher Curl
a) b) c)
Conclusion
In conclusion eccentric exercise is known to lead to greater hypertrophy than comparable resistance exercises. However we should proceed with caution when applying this to resistance programs due to the application difficulties and the extensive muscle damage and DOMS that can associated with it. Various examples can be seen above but feel free to contact me with any further queries or ideas.
[16]Mike, J. (2015). How to incorporate eccentric training into resistance programs.. Journal of Strength and Conditioning Research.
