Regardless of which process strength coaches use to create training programs, such a process must have a step where exercises are selected. Exercise selection is always executed based on certain criteria that include:
- Scientific research
- Foundational bio-mechanical principles
- First person experience with athletes.
It is logical to assume that the better the criteria, the greater the likelihood of a positive outcome of the training program.
Criteria include principles, strategies, and tactics. This article suggests the 1st Principle of exercise selection, followed by a description of primary exercise selection strategies. Last, current research findings on the effects of single-joint vs multi-joint exercises are discussed and concrete guidelines for exercise selection are suggested.
1 First Principle of Exercise Selection
The first principle of exercise selection could be that:
Any exercise ever performed must – in the short or the long run – improve the athlete’s ability to practice or compete.
If these criteria are not met, how do we explain that the exercise is in the program?
Even exercises that might be included for fun and variation can be said to meet the above criteria.
Why would we include an exercise in the program where the purpose is “just” fun? The answer is that we would include exercises for fun so that the athlete stays in our program. What is the outcome if of the athlete staying in the program? With practice, over time, the ability to practice and compete is improved.
Exercise Selection Strategy (Part I): Bio-mechanical specificity
For athletes, the ability to practice and compete involves the ability to safely, effectively and repeatedly sprint, cut, kick, throw or perform any other sporting movement.
How do we know which strength and conditioning exercises will improve the above abilities?
The primary strategy is to select exercises based on biomechanical specificity which means that there is a certain biomechanical resemblance between the training movement and the sporting movement. (10)
This strategy is often misunderstood. Correctly used the exercises should stimulate, not simulate the sporting movement. (7,8) More accurately, the exercises must always stimulate the ability to practice or compete in the sport. The most foundational exercises do not necessarily look that much like the sporting movement. As the movement patterns are built the resemblance to the end goal become gradually more obvious.
Example: Especially eccentric knee-flexor strength may be important for preventing hamstring injuries during sprinting. The first video below shows a more foundational hamstring exercise that does not really look like sprinting. In contrast, the second video shows a hamstring exercise where the resemblance to sprinting is more obvious
Exercise Selection Strategy (Part 2): Intra- and inter- muscular coordination
Train the movement, not the muscle – one of the original taglines of functional training – is a logical proposition when the end goal is to improve the ability to perform a sporting movement.
However, the body is only a strong as its weakest link. (6) Further, the basic phenomenon is that the body avoids positions of weakness and seeks positions of strength. Thus, practicing complex movements with identifiable weak links may inhibit long term progress as far as that particular movement.
Therefore, a longer training cycle has an early phase where the primary focus is to develop any identified weak links. In this early phase, there is a secondary focus on practicing a version of the final movement that challenges the identified weak link. As the weak links become strength’s the focus is reversed and practicing the complete movement is the first priority. Train the muscle, then the movement is the (over)simplified tagline for this dynamic that is also expressed as “first isolate, then integrate.”
How could we describe the benefits of exercises that focus on weak links? How could we describe the benefits of exercises that focus on practicing the movement?
The concepts of intra- or inter-muscular coordination describe which exercises that focus on weak links aim to do. (9)
Intra-muscular coordination
“Another possibility for improved power results from improved intra-muscular coordination. The term “intramuscular coordination”, describes in the author’s opinion the relation between excitatory and inhibitory mechanisms for one muscle for a specific movement.” (93)
Inter-muscular coordination
“A further way to improve power results from improved inter-muscular coordination. Inter-muscular coordination describes the ability of all muscles involved in a movement, agonists, antagonists, and synergists to corporate wholly with respect to the aim of the movement.”
It is obvious that inter-muscular coordination requires the use of multi-joint exercises. However, intra-muscular coordination can be developed with both single-joint exercises or targeted multi-joint exercises.
3 Tactics – Single-joint or multi-joint exercises.
The following section offers some research-based guidelines regarding the benefits of single joint vs multi-joint exercises.
The most foundational aspect of the choice between single-joint and multi-joint exercises is the ability to develop intra- or inter-muscular coordination:
- Single joint exercises are more effective to strengthen a weaker muscle group, but the single joint exercise must eventually be replaced with a multi-joint exercise to obtain more impressive strength increases. (3)
- Multi-joint exercises offer an increased opportunity to develop inter-muscular coordination through the involvement of multiple segments of the body. (6)
Example – Frontal Plane Stability in for sprinting
Early phase 6 weeks:
A1. Forward Walking Lunges with a pause to demonstrate balance as the trail leg passes the stance leg. The exercise can be vertically loaded with a vest, dumbbells or a barbell.
B1. Standing Hip Hike
Later phase (6 weeks)
A1. Forward Walking Lunges Dragging a Sled, explosive execution. Add vest if needed.
B1. Standing Hip Hike is included with low volume as a warm-up or finisher exercise.
Structural strength, including hypertrophy (muscle mass), is a foundation for developing maximal strength:
- Single joint exercises and multi-joint exercises for the same target muscle group – with similar RM loads – results in similar levels of electromyographic activity. (1)
- With the use of multi-joint exercises, synergists might fatigue before prime movers and limit the stimulus of the prime movers OR synergists might not be sufficiently stimulated due to the dominance of the prime movers. (1)
- To the extent that the same fibers of a target muscle experience the same stress (load) the hypertrophic response from single joint and multi-joint muscles is likely going to be similar. (2,5) However, due to different patterns of muscular hypertrophy between single-joint and multi-joint exercises (so-called regional hypertrophy) a combination of a single joint- and one or more multi-joint exercises may be required for complete muscular development. (1,4)
- Compared to using multi-joint exercises to develop the same target muscles, single joint exercises may result in faster increases in muscle mass due to a shorter duration of neural adaptations (1,2)
With respect to the development of maximal strength and Vo2max:
- Multi-joint exercises may result in a greater training stimulus due to greater load lifted. (2)
- Multi-joint exercises may have greater potential as a tool to develop V02max due to a higher muscle mass involved. (5)
Application Summary
To utilize the information presented in this article strength coaches must work from a needs analysis of the sport and assessment of the athlete’s strengths and weaknesses. (10)
The body can be understood as a kinetic chain that is not stronger than its weakest link(s). For this reason, there is an initial emphasis on developing weak links through targeted multi-joint exercises or single joint exercises.
Once the weak links have become strengths the emphasis switch to practice the final, key movement.
References
- Gentil P, Fisher J, Steele J. A Review of the Acute Effects and Long-Term Adaptations of Single- and Multi-Joint Exercises during Resistance Training. Sports Medicine 2016
- Gentil P, Soares S, Bottaro M. Single vs. Multi-joint Resistance Exercises: Effects on Muscle Strength and Hypertrophy. Asian J Sports Medicine. 6(2): 1-4. 2015.
- Giannakopoulos K, Beneka A, Malliou P, Godolias G.Isolated vs Complex Exercise In Strengthening The Rotator Cuff Muscle Group. Journal of Strength and Conditioning Research. 18(1):144-148. 2004
- Ribeiro AS, Schoenfeld BJ, Sardinha LB. Comment on: A Review of the Acute Effects and Long Term Adaptations of Single and Multi-joint Exercises During Resistance Training. Sports Medicine. 2016
- Paoli A, Gentil P, Moro T, Marcolin G, Bianco A. Resistance Training with Single vs. Multi-joint Exercises at Equal Total Load Volume: Effects on Body Composition, Cardiorespiratory Fitness and Muscle Strength. Frontiers in Physiology. Vol 8. Page 1-8. 2017.
- Teixera CVS, Evangelista AL, Novaes JS, Grigoletto MES, Behm DG. You are Only as strong as Your Weakest Link: A Current Opinion about the Concepts and Characteristics of Functional Training. Frontiers In Physiology. Vol 8, page 1-8. 2017
- Stone MH, Stone M, Sands WA. Principles and Practice of Resistance Training. USA: Human Kinetics; 2007. 243-253 p.
- Siff M. Supertraining. 6th Ed. The Means of Special Strength Training. USA: Supertraining Institute; 2004. 240-246 p.
- Schmidtbleicher D. Training for Power Events. In Strength and Power in Sport, Chapter 18, p. 385-395. Blackwell Science; 1992.
- Jensen K. Needs Analysis of Sports. The Foundation of Success With The Flexible Periodization Method. https://yestostrength.com/fpm-move-better.html