Science Behind Concurrent Training

Simultaneously training for adaptations associated with resistance and endurance training (RT & ET), otherwise known as concurrent training (CT), is widely debated by fitness professionals and strength coaches alike. CT has been criticized due to the potential for chronic overreaching, as well as the competing adaptations associated when performing RT and ET, concurrently. However, if programmed carefully, CT can produce a lean and sculpted physique, while obtaining a high level of fitness as measured by health aspects as well as athletic parameters. Therefore, the purpose of this article is to elucidate the ways in which the adaptations associated with both RT and ET can be maximized when training concurrently.

What is Concurrent Training or CT?

Concurrent Training is a combination of resistance and endurance training to improve on all elements of fitness. As long as you are not practicing a sport that requires only muscle strength, such as weightlifting, or only extreme endurance, such as cycling for long distances, combining resistance exercises with endurance exercises is optimal, especially if you are practicing a sport that requires strength and endurance such as basketball, boxing or football that requires improving all components of fitness.
Concurrent training also stimulates muscle building to improve metabolic rates, keep fat percentage low, and improve body shape.

Research and theories behind Concurrent Training

In research published in 1980, it was found that cardio negatively affects the increase in physical strength. It does not negatively affect the increase in VO2Max or the body's ability to consume oxygen during exercise. In other words, doing cardio negatively affects muscle building, but weight lifting does not negatively affect the increase in breathing length. In the research, high-intensity cardio exercises were followed.
After this research, many studies were conducted on simultaneous training with different types, durations, and dates of cardio exercise each time to determine the best programs for each sport.

There are two main theories on which Concurrent training is based.

1. Molecular Signaling Theory
Molecular signal theory

It is well known that endurance and resistance training, such as muscle building and strength building, is done through specific pathways known as AKT and mTOR pathways. Resistance exercise results in greater strength and muscle stretching, as well as muscle damage and swelling, which increases AKT and mTOR pathways.
Weight lifting exercises use a larger group of muscles and have the ability to produce great strength and increase muscle tone as a whole. On the other hand, exercises like Drop Sets and Giant Sets contribute more to metabolism and cell swelling.

On the other hand, long, repetitive exercises that cause muscle contractions of low intensity activate other pathways, including AMPK and CaMK enzymes, which are responsible for the changes associated with endurance exercises, such as the biogenesis of mitochondria, which are the energy unit of cells, so you can walk and run for a longer and more effective time.

When AMPK enzyme activity is increased, the mTOR pathway is inhibited, which is the basis for the molecular signaling theory. Activation of AMPK reduces and may impair muscle response to resistance exercise and thus no amplification by inhibiting the mTOR pathway and increasing protein breakdown by other pathways.
The mTOR pathway can also be inhibited separately from the AMPK enzyme by increasing proteins called SIRT.
The bottom line is that when you do cardio exercises while following a program to increase resistance exercises, it can have a negative effect on muscle hypertrophy and strength.

This does not necessarily mean that cardio exercises reduce muscle gain and hypertrophy. It is common to increase endurance and improve resistance training results with synchronized training. In some cases, resistance training can regulate the enzyme AMPK and aerobic exercise can stimulate an increase in mTOR activity, so positive effects can be obtained when the strength, volume, and rate of each exercise are adjusted.

It should be noted that the results of these studies do not necessarily apply to all cases or to predict the future of changes that will occur in the body. For example, athletes who do not have experience with synchro-training can get its effects after a period of acclimatization to a new exercise program. Also, the effects can appear after the accumulation of resistance and endurance exercises for a period as a result of increasing the intensity of the exercises and increasing the loads. For example, in 1980 research they found that the effect was not seen before the eighth week of exercise.

Since the molecular signaling theory changes according to the exercise program followed by the person, the exercises must be described according to the person's experience in performing the exercises in addition to taking into account the exercise program that is being followed at the moment.

2. Overtraining Theory

Lack of proper regulation of resistance and endurance training can expose athletes to overtraining. For example, high-intensity endurance exercises combined with high strength training exercises can make recovery difficult, increase the likelihood of injuries, and negatively affect muscle growth from overtraining.
Since the first study in 1980, scientists have conducted hundreds of studies on Concurrent training to come up with the best fitness programs for most sports such as weightlifting and cardio at the same time.
The studies discuss the duration of cardio exercises, the type of movements, the time apart from weightlifting exercises when exercises are exercised before and after weight lifting, the intensity of cardio exercises, whether low-intensity or high-intensity, and other factors.

How do you include aerobic or cardio exercises for a weightlifting program?

There are many studies that give effective suggestions on how to include aerobic and cardio exercises in a weight training program.

1. Cardio type

The best type of cardio exercise is the one that simulates the movements of weightlifting exercises, as it contributes to building more muscles and avoids losing them.
In a study published in 2009, it was found that exercises on the bike do not negatively affect the muscles of the legs, such as running on the electric treadmill, because the exercises on the bike mimic the exercises of the squats and Leg Press, and therefore you will not find an athlete exercising on the bike has weak leg muscles.
Another example is that jump rope exercises simulate exercises for the calf of the foot and forearm, and therefore jump rope exercises increase the size of the calf muscle.
Sprinting at high speed also simulates leg exercises, which is different from brisk walking where the movements are different.
Circuit training exercises are also performed in which complex exercises are performed with light weights and high repetitions without any rest periods. It is considered one of the best cardio exercises to strengthen muscles, but it requires a commitment to go to the gym and is difficult in the commitment process.

2. Separate cardio exercises from weightlifting

Studies show that the time difference between cardio and weight training should not be less than 8 hours if you are working out on the same day. The best thing is to do cardio one day and weight training the next. Another suggestion is to do cardio five minutes before weightlifting to warm up, and then do cardio for 20 minutes after lifting weights to cool down.

3. Cooling down after weight lifting

One study was conducted on three groups of women doing weight lifting exercises. The first group did only weight lifting, the second group did low-intensity cardio for 20 minutes after weight training, and the third group did moderate-intensity cardio after weight training. Studies have found that the third group that did moderate-intensity cardio exercises had faster muscle recovery and less muscle soreness or DOMS.

4. High-intensity interval training or HITT

High-intensity interval training is best for building muscle as it strengthens the heart muscle, improves blood circulation, and increases breathing. Long, regular breathing is important for many types of exercise, such as swimming and weightlifting.
Also, high-intensity interval training is 10 to 15 minutes long, so it will not cause muscle pain and will not interfere with the speed of muscle recovery.
HITT exercises are best done on rest days because they are considered separate exercises in themselves.

5. Volume of exercises and diet

The volume of exercises should be appropriate to your diet. For example, eating only 1,500 calories per day with weight training 5 days a week and cardio 4 times a week is not enough and may overtrain you and put you at risk of injury.

Concurrent Training Objectives

How you do cardio exercises varies depending on the purpose of the Concurrent training. These are some of the most appropriate Concurrent training protocols depending on the purpose of the training.

1. Muscle Hypertrophy

Muscle Hypertrophy

  • Do endurance exercises after resistance training if the endurance exercises are low to medium intensity. Resistance exercises will target different muscles than resistance exercises. It is not yet known if the molecular signaling theory applies to specific muscles or to the body as a whole, regardless of which muscles are exercised. In the event that the effect targets specific muscles, it is necessary to do weight lifting exercises that target the upper body, followed by cardio exercises that target the lower body, such as riding a bike.
  • Do endurance exercises before resistance exercises if there are three to six hours between exercises for recovery. During recovery, eat carbohydrates and some protein to provide your body with more energy.
  • Do low-intensity endurance exercises such as cycling and swimming to avoid extra stress on your joints and muscles.
  • Do moderate-intensity, low-intensity endurance exercises to improve heart health and increase blood flow to active muscles as a form of recovery and energy management.
  • Do Zone 1 light exercises before lifting weights.
  • Do Zone 2 moderate-intensity exercises on rest days or as separate exercises to improve heart health and increase blood flow to the muscles.
  • Do high-intensity exercises Zone 4 and 5 after muscle amplification exercises as a kind of metabolic stress. These exercises target the same muscles and consume energy in the same way as muscle amplification and strength exercises.
    Muscle Hypertrophy

2. Increase Muscle Strength

  • Do endurance exercises after resistance training if the endurance exercises are low to medium intensity. Resistance exercises will target different muscles than resistance exercises.
  • Do endurance exercises before resistance exercises if there are more than six hours between exercises for recovery. During recovery, eat carbohydrates and some protein to provide your body with more energy. It is important that muscle fatigue be kept as low as possible, as strength training exercises mimic the same technique as weightlifting exercises and are high-intensity exercises.
  • Do low-intensity endurance exercises such as cycling and swimming to avoid extra stress on your joints and muscles.
  • Do Zone 2 moderate-intensity exercises as a separate exercise session to improve heart health, increase blood flow to muscles, and increase recovery.
  • Do Zone 4 and 5 high-intensity cardio exercises to improve your ability to lift high-volume weights.

3. Increase Power

  • Do endurance exercises after resistance training if the endurance exercises are low to medium intensity.
    It is best not to do endurance exercises before resistance exercises. If it is unavoidable to do endurance exercises before resistance, recover as long as possible while providing the body with food and avoid targeting the same muscles with exercises. Exhausting strength-building exercises can be dangerous and cause many injuries. It is best to rest for more than 24 hours.
  • Do low-intensity endurance exercises such as cycling and swimming to avoid extra stress on your joints and muscles.
  • Do Zone 2 moderate-intensity exercises as a separate exercise session to improve heart health, increase blood flow to muscles, and increase recovery. To improve recovery on rest days, you can add movement and stretching exercises to low-intensity aerobics.

4. Long-Event Endurance Sports

cycling

  • Resistance training after endurance training is the best protocol as it avoids pre-exerting yourself before endurance training and avoids any disruption of the mTOR pathway.
  • Resistance exercises should focus on complex and complex exercises that include different muscles and more than one type of movement. Use weights about 70% to 90% of your 1RM or One Repetition Max. 1RM is the maximum weight you can lift for each muscle or exercise.
  • Performing these exercises is important for building a strong, healthy body that can withstand high-intensity endurance exercises for a long time by building flexible tissues and strong ligaments.
  • Do not do exercises that mimic the movements you practice in your sport. Stick to other exercises.

5. Short-Event Endurance Sports


endurance sports

  • Resistance training after endurance training is the best protocol as it avoids pre-exerting yourself before endurance training and avoids any disruption of the mTOR pathway.
  • Resistance training is very useful for sports with low endurance such as running 400 to 800 meters or cycling. Use weights of about 70% to 100% of your 1RM or One Repetition, Max, to build more muscle mass and tone your muscles.
    Also, strength training exercises can be done with about 30% to 70% of your 1RM or One Repetition Max depending on the requirements of your sport. Sports that require high-intensity bursts of exertion benefit the most from performing exercises according to this protocol.
  • The selection of exercises must be accurate so that part of it simulates some of the movements that you make during exercise.

6. Team sports or Mixed-Type Sports or Team Sports

Team sports

Team sports differ in their requirements depending on the sport itself and the position you play in. By analyzing the requirements, each sport can create its own protocol. From the previous figure, you can select the requirements for different sports. Start by identifying the requirements of your sport in terms of strength and endurance, then the required movements and energy required according to your position to get the most out of your training sessions.


Chart: Olympic lifting vs marathon

Conclusion

Concurrent training is the combination of cardio and resistance training in one training session or at a close interval that enables you to get greater results because resistance training and endurance training have different ways of affecting muscles down to the cellular level and may negatively affect your goals.