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Muscle contractions occur throughout all exercise and human movement. Preparing our clients to effectively lift weights includes teaching them how to oppose resistance applied to a muscle. If clients follow their training program using the right lifting techniques, they're more likely to achieve increased muscle size and strength gains. Being able to control the demand and load placed upon each muscle is key to optimal results.
It is crucial to first understand how a muscle contracts to produce force. In short, there are two proteins found in sarcomeres. The sarcomere located within a muscle fiber contains two proteins called actin and myosin. They are responsible for forming cross bridges and attaching to each other to create muscle contractions.
The sliding filament theory is one of the many explanations for how muscles produce force. The type of exercise your client engages in will determine the predominant use of fast-twitch muscle fibers or not. These fibers fatigue quicker than others, but act in high force production movements.
Three main muscle contractions occur in almost every exercise performed. Concentric muscle contractions occur when a muscle shortens to move load placed on the body. If a client is performing a bicep curl, they will concentrically contract the muscle when they lift or curl the weight upward. For the arm to perform this movement the biceps must contract and it does so by the muscle shortening.
This type of contraction is the opposite of a concentric muscle action. Lowering the weight in a bicep curl elongates or lengthens the muscle, which is part of eccentric strength training. When a muscle lengthens through the eccentric phase it has the greatest force production capability. The rate at which actin and myosin detach from one another is greatly inhibited during the eccentric phase, which allows for more contractions and higher force production.
When people hear muscle contractions, they immediately assume the body is moving in some manner, but isometric muscle contractions are different. During isometric muscle contractions, there is no change in muscle length due to a static joint angle. If a client statically holds a dumbbell during the biceps curl at the halfway point in the concentric phase, the muscle will isometrically contract. This phase allows the client to sustain the load at a fixed angle.
Why should your clients focus on eccentric training? Let's break down the top three reasons: strength gains, muscle growth, and enhanced rehabilitation.
When a client's goal is to increase strength, you prescribe resistance exercise consisting of lifting heavier weights with lower repetitions and maximal output. Strength and conditioning programs involve targeting all muscle groups and movement patterns to build muscle and increase muscle strength. Common exercises used in this manner can include a barbell back squat and barbell bench press.
Concentric strength is trainable to certain levels, but can only be so strong compared to a client's eccentric strength levels. Titin is a protein found in the eccentric phase more so than in the concentric phase. This protein provides an increased amount of force in eccentric muscle actions. Although found in both concentric and eccentric muscle contractions, titin only willing performs optimally when skeletal muscles stretch and lengthen.
The force applied to a muscle during eccentric training is greater than the opposing force applied back. This is important so your client can workout by resisting force on the eccentric portion of an exercise. Have them aim to avoid letting the weight return to the starting position for as long as possible. Purposefully increasing the time the muscle is under this stress will help your clients generate a higher amount of force and build greater strength over time.
You may have heard once before that a bigger muscle is a stronger muscle. Strength and muscle do have a direct correlation to a certain extent. This is dependent on the type of strength training your clients perform.
During eccentric training, there are higher amounts of micro-tears that occur, which create muscle soreness and muscle injury. Due to such a great amount of muscle damage you can expect clients to experience DOMS or delayed onset muscle soreness more than any other exercise will provide.
The extent of muscle breakdown causes connective tissue surrounding the muscle to undergo higher levels of injury, which creates more potential for DOMS, but also greater muscle growth through recovery. This type of injury is not necessarily detrimental, as any time a client performs a workout, they are creating tears within the muscle. It is the levels of injury that determine how serious it could be. Therefore, it is important when implementing eccentric strength training into your client's exercise to be especially cautious.
In addition to increased muscle mass and strength gains, eccentric training can help prevent muscle breakdown. This is a trending topic in the older adult population because as we age muscle mass begins to atrophy.
It has been found that eccentric training helps prevent muscle wasting in sarcopenia and many other chronic diseases. There is tremendous evidence that supports the effects of eccentric exercise on body composition and other health issues.
Consider using eccentric training to increase muscle mass and strength for those with serious injury, all athletes, and the general client coming to you for your professional help. The more muscle damage you safely and effectively cause the greater the muscle growth and results. With increased muscle mass, athletes experience higher levels of performance and less injury.
Ready to add eccentric training to your clients' programming? Review these key techniques to maximize results.
Tempo can be a huge tool for taking full advantage of eccentric training. This technique influences how long each muscle remains under tension. In an eccentric muscle action, the weight applied should always exceed the force developed by the muscle itself. But if you could slow down the time it takes to lower the weight, you will increase the benefits. The negative portion of the repetition—eccentric contraction—is where a great deal of energy absorbs through loading the muscle.
Slow and controlled eccentric repetitions are beneficial for the muscle to stay under tension for a longer time. Muscle fibers stretch further while contracting, which makes actin and myosin form more cross bridges. Eccentric training uses less energy which is why it is easy to forget how much muscle damage is taking place. Be sure to monitor the amount of eccentric exercise your client performs to avoid too much soreness.
Heavy lifting puts a greater demand on the eccentric contraction. There is a greater degree of stretching and muscle damage and you also take advantage of being the strongest at this point in the exercise.
Have your client safely perform cheat reps if needed to bring the heavy weight to the top of the movement. You can help them do this during a training session. Ensure the entire load is put on muscles when performing the eccentric portion of the exercise. If a client is performing these without a partner or trainer present, have them perform unilateral eccentric exercises so they can use the other side of the body to help them place the weight in the correct position to perform the eccentric repetition.
Weighted dips, preacher curls, dumbbell overhead triceps extensions, and lateral raises do not need assistance. These are great exercises to perform solo and load up with heavy weights while limiting the risk of injury. Starting the weighted dip by jumping up straight and then lowering down slowly is what will emphasize the eccentric contraction. The same idea applies to the overhead triceps extensions by pressing the dumbbell up overhead and lowering it back down slowly to rest on the shoulder and repeating.
During a training session or if they have a partner when working out without them is when they can receive assistance to perform forced repetitions. This is also known as spotting, but when reaching volitional fatigue at the end of a set you help them squeeze out a few more reps. Exercises that promote this type of training are negative bench presses, military presses, leg extensions, and leg curls.
There are so many beneficial exercises that you can get the most out of with eccentric training.
Upper body exercises that can focus more on the eccentric portion include the following:
Overhead triceps extensions
Hanging leg raises
Lower body exercises:
Standing calf raises.
Remember, all exercise movements have eccentric contractions so you can expand beyond these lists.
Combining isometric and eccentric training techniques are also very beneficial due to increased muscle tension. The main goal of eccentric training is to increase the time under tension while elongating the muscle. By performing techniques like pause reps during the eccentric contraction you immediately switch to an isometric contraction. Leading to more muscle damage forcing it to repair even stronger than before.
Help your clients reach maximize their gains and reach their tops fitness goals:
Any type of muscle injury or tear initiates an inflammatory response. When this occurs, damaged muscle fibers encounter the presence of macrophages, lymphocytes, and even creatine kinase. Macrophages and lymphocytes are white blood cells responsible for fighting against bacteria in the body and remove any extra cellular debris. This helps increase muscle growth, repair, and recovery.
Eccentric training works well because of the human body's ability to mechanically load and create great stimulus to the skeletal muscle in these certain exercise phases. The ability to produce greater forces during eccentric actions is what induces muscle hypertrophy and maximal output. This training shows a great trend towards increased muscle cross-sectional area as well.
Exercise intensity is not all about heart rates beating fast. Intensity is used in terms of a one repetition maximum to decide the weight your body needs to take on to optimally perform and get better.
Curling up a 50-lb. dumbbell is not easy for most individuals. Although if you were to hand that 50-lb. dumbbell to your client so they could start the movement at the top by lowering it back down it would be much easier.
This is an exact example of what is meant by eccentric contractions or the lowering phase producing more force. Your client can do this and expend much less energy than if they concentrically curled the weight up.
With this type of lifting your client can use heavier weights, which is a form of increased exercise intensity, all while expending less energy. There is a much lower energy demand for eccentric training than concentric muscle contractions.
Eccentric strength training can even apply to rehab exercise to help improve force production, strength, and lean body mass in those who recently had some type of injury or surgery. A lot of times you will see techniques like this used in ACL injuries especially for strengthening the quadriceps femoris muscle.
Knowing the differences between all the muscle contractions that happen during exercise is vital to help clients reach the goals they set out to achieve. The importance of this ranges from avoiding plateaus to improving sports performance for athletes. Become an expert on muscle contractions and help lead clients to a higher fitness level through ISSA's Fitness Trainer course.