Muscle Fatigue Symptoms: How to Prevent & Treat Them

When a client is fatigued, that’s one thing. A good night’s rest or a cup of pre-exercise coffee can help them restore their energy levels. It’s something completely different when their muscles are tired.

When fatigue is muscular, they lack the physical energy needed to power through their fitness-boosting workouts. Their performance suffers, as does their self-esteem. What type of muscle fatigue symptoms should you watch for as a personal trainer?

Most Common Muscle Fatigue Symptoms

The primary symptom of fatigue is muscle weakness. They’re not able to lift the same amount of weight as they did during previous training sessions. Or their muscle appears to tire more quickly. They can’t make it through their reps and sets. Their muscle contraction doesn’t produce enough force.

Some muscle weakness from time to time is normal. Maybe they’re just getting over an illness or the previous workout was particularly hard. Progressive muscle weakness, on the other hand, could be a sign of muscle fatigue. So too is muscle weakness that seems to persist over time.

Muscle weakness isn’t the only symptom of fatigue. A few additional exercise-related muscle fatigue symptoms include:

• Muscle cramps, or when the muscle tightens involuntarily

• Muscle spasms, also commonly referred to as muscle twitches

• Muscle soreness or pain

All of these can signal fatigued muscle. So, if a client mentions them, it is important to listen. Changes may need to be made to their workout plan to help reduce the fatigue.

What Causes Muscle Fatigue?

To prevent and treat muscle fatigue requires that you understand what causes it. When related to exercise, research reveals that these causes are numerous. 

One explanation is that exercise changes neurotransmitter concentrations in the body. This causes fatigue within the central nervous system. Since the central nervous system controls muscle contraction, the fatigue extends to this function. Another theory is that exercise impairs the body’s release of calcium. This can cause fatigue within skeletal muscle fibers.

If the exercise is high-intensity, this can lead to muscle fatigue as well. The body isn’t able to make adenosine triphosphate (ATP) as fast as it needs. So, balance within the muscle tissue is thrown off. This imbalance results in fatigue.

Yet another potential explanation for muscle fatigue is glycogen depletion. Glycogen is one of the primary energy sources for muscle contraction. Yet, the end product of glycolysis, which is the process of converting glucose to ATP, is lactic acid. 

Lactic acid buildup is typically associated with post-exercise muscle soreness. However, the increase in lactic acid may also contribute to metabolic changes. These changes are thought to impair muscle force. 

What does all of this mean in simple terms? If you want to prevent progressive weakness and fatigue, the body needs time to recover. It needs to be allowed to return to balance between exercise sessions. Specifically, muscle fiber must be given enough time to heal.

Muscle Fatigue Prevention via Effective Muscle Recovery

The absolute best way to avoid muscle fatigue is to make rest and recovery a priority. Create workout plans that include days off after especially tough exercise sessions. Incorporate active recovery to enhance blood flow, further aiding in muscle recovery.

Not only can inadequate recovery lead to muscle fatigue, but it can also increase injury risk. Muscle weakness means ineffective support of the skeletal system. This puts the spinal cord and extremities at greater risk.

Typically, muscle fiber needs 24-48 hours to fully heal. If a workout is particularly taxing, 72 hours may be more appropriate. 

You can give muscle adequate recovery time by alternating upper and lower body sessions. This enables clients to still reach their fitness goals without overtraining. It also keeps them from pushing certain muscle groups too hard. An example of this schedule is:

• Monday – upper body

• Tuesday – lower body

• Wednesday – rest day

• Thursday – upper body

• Friday – lower body

• Saturday – rest day

• Sunday – active recovery day

Additional Muscle Fatigue Prevention Options

In addition to recovery, there are a few other ways to help prevent fatigue and its related muscle weakness and soreness. Three to consider are stretching, hydration, and a healthy diet.

Stretching

Reinforce the importance of stretching before and after exercise sessions. Stretching prior to exercise prepares skeletal muscle for the upcoming movements. Stretching post-exercise helps the body get rid of lactic acid. This reduces muscle soreness and fatigue.

Stretches chosen should elongate the muscle being worked in that day’s exercise plan. For example, if it is a lower body workout day, choose stretches aimed at the quads and hamstrings. Upper body days should include stretches aimed at the arms, back, and chest.

Hydration

Hydration is also critical for preventing muscle fatigue. If the client is dehydrated, the heart has a harder time pushing blood throughout the body. This means the muscle isn’t going to get the oxygen or nutrients it needs to sustain the exercise or to recover. It also means that lactic acid isn’t going to be removed as efficiently. So, muscle weakness and fatigue results.

Everyone has different hydration needs. A general guideline is to have the client drink two cups of water directly before the exercise session. They should continue to drink every 15 minutes thereafter. Encourage them to rehydrate after the workout as well. If it is a long workout, add electrolytes to boost recovery even more.

Healthy Diet

Carbohydrates supply the glucose needed for ATP production. Protein is the building block of muscle, also playing an important role in recovery. Thus, a diet that includes both of these macronutrients can help reduce muscle weakness and fatigue.

How much a client needs of each is dependent, in part, on their fitness goals. An endurance athlete needs more carbs, for example. Yet, a client focused on boosting muscle strength benefits from more protein. The main point to stress is that they should eat foods from all food groups for maximum skeletal muscle health.

How to Relieve Muscle Fatigue Symptoms

Because muscle fatigue is often characterized by soreness, clients may find some relief with hot or cold therapy. Applying a heating pad can help relax the muscle. This reduces the tension causing the sore muscle. Heat can also stop a muscle cramp or muscle spasm. 

If the muscle is just sore, ice may be the better option. Ice helps by reducing inflammation. It also decreases muscle pain by numbing the problem area.

Since lactic acid can contribute to muscle weakness, clients may also benefit from massage. Massage helps by improving blood flow to the muscle. This lets more nutrients in and allows for more toxins to be released. Together, this reduces muscle aches and pain.

When Muscle Fatigue Requires a Doctor’s Visit

It should be noted that muscle weakness could also be a sign that something else is going on. Health conditions such as chronic fatigue syndrome and fibromyalgia are both characterized by reduced muscle strength. 

A neuromuscular disorder can also cause muscle strength reduction. The Mayo Clinic explains that myasthenia gravis is one. This condition occurs when there is a breakdown between muscle and nerves. Myositis is another. Myositis refers to any condition that leads to muscle inflammation. This inflammation increases weakness and fatigue.

If a client complains of muscle fatigue or you notice changes in their performance, it may be helpful to go through a symptom checklist before every training session. Make note if a particular symptom appears or persists. This can help you determine if the issue is getting better or worse.

If clients continue to experience a muscle fatigue symptom despite attempts to reduce it, a doctor’s visit may be needed. This can help to rule out a muscle disorder or other potential causes. A doctor’s appointment is also recommended in cases of chronic fatigue, or fatigue affecting more than just the muscle. The doctor can thoroughly assess their patient to get a better understanding of what is going on.

In the meantime, encourage them to take time off from their training schedule. Give the fatigue time to naturally dissipate. It is possible that they are overtraining. This creates whole-body fatigue that contributes to fatigue in the muscle. 

Getting some much-needed downtime may be enough to boost muscle contraction force. It creates a sort of reset for the body. In this way, muscle recovery is just as important as doing exercises that promote muscle growth.

Want to learn more about potential muscle weakness causes and how to treat them? The ISSA’s Strength and Conditioning Certification provides a more in-depth look at muscle recovery and injury prevention. It also offers several strategies for treating fatigued muscle and its related soreness.

Resources

Wan, J. J., Qin, Z., Wang, P. Y., Sun, Y., & Liu, X. (2017). Muscle fatigue: general understanding and treatment. Experimental & molecular medicine, 49(10), e384. https://doi.org/10.1038/emm.2017.194 

Myasthenia gravis - Symptoms and causes. Mayo Clinic. (2021). Retrieved 24 May 2022, from https://www.mayoclinic.org/diseases-conditions/myasthenia-gravis/symptoms-causes/syc-20352036.