Concurrent Training: A Science-Backed Guide

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Last Updated:
March 1, 2024

Key Takeaways:

  • Concurrent training presents a holistic approach to fitness by combining strength and cardiovascular exercise.
  • The interference effect describes the potential adverse effects of endurance training on strength development.
  • Interference effects may be due to fatigue, fueling, and molecular changes from training. 
  • Adjustments in your training variables can help you reap the benefits of cardio and strength training without losing momentum.
  • Recovery plays a significant role in supporting concurrent training protocols through balanced nutrition and rest. 

What is Concurrent Training?

Concurrent training combines strength and aerobic training within a program. You can perform both types of training within one session or one week. 

Cardio and strength training protocols present very different adaptations to the body, so optimizing your training pays off for your health and your performance. The Physical Activity Guidelines for Americans recommend 150 minutes or more of moderate-intensity physical activity and at least two weekly strength training sessions (1).

Dr. Robert Hickson was the first scientist to research the concurrent training model. In his 1980 study, one group completed only resistance training, one only endurance training, and the third completed both forms of exercise over 10 weeks (2). He found that the concurrent training group increased VO2max by 20% and leg strength similar to the endurance and strength groups. However, the endurance group only improved VO2max, and the strength group improved strength—highlighting the benefit of concurrent training in improving different fitness variables simultaneously.  

Here, you’ll learn everything you need to know about concurrent training and how to manage the interference effect to build an effective program for lasting strength and endurance. 

The Fundamentals of Concurrent Training

Concurrent or hybrid training is the simultaneous integration of resistance and endurance exercise in a periodized training program. While both forms of exercise enhance health and performance, they create unique adaptions in the body.

 

With chronic resistance training, you can expect to see improved (3)

  • Muscle activation by the nervous system
  • Fiber hypertrophy (increased muscle mass)
  • Maximal contractile force (improved muscle strength)

With chronic aerobic training, you can expect to see improved (3)

  • Mitochondrial density 
  • Oxidative capacity of trained muscle fibers
  • Substrate metabolism (more efficient at using fat for energy)
  • Aerobic capacity 

These long-term adaptations of each training modality come from different cellular pathways and enzyme activity in the muscle. Suppose you are working at your maximal capacity for strength and endurance. In that case, you may hit against the interference effect, which can potentially negate a signal to either build muscle or build oxidative capacity. 

Resistance training signals a protein kinase (an enzyme) called mTOR that stimulates muscle protein synthesis (4). Conversely, repetitive endurance training, like running and cycling, increases levels of a different protein kinase in the cell, called AMPK, which regulates mitochondrial biogenesis (4). High concentrations of AMPK suppress the activation of the mTOR pathway, potentially limiting your ability to stimulate muscle hypertrophy following a workout in the short term. 

Not all concurrent training impedes strength development, however. The interference effect is only a cause for concern if you work towards absolute max strength and power, like elite powerlifters or sprinters. If you have a variety of strength and fitness goals, the interference effect is nominal, so concurrent training is perfectly safe and boasts various benefits. 

Benefits of Concurrent Training

Strength and cardiovascular endurance are essential for overall health and athletic performance. Compared to cardio or strength training alone, studies show strength and aerobic capacity improvements when both are performed in the same program (5)

Here are 6 benefits of concurrent training: 

  1. Increase athleticism: Adding resistance training into your endurance routine creates neuromuscular adaptations that increase power and enhance the stretch-shortening cycle. Sports science studies show that you produce more force per step and rebound faster with these training regimens—spending less time on the ground and more time accelerating forward (6)
  2. Injury prevention: Around 70% of running injuries are overuse-related (7). Studies show that the neuromuscular training you get from resistance training may reduce your risk of injury by improving running mechanics, muscle weakness, and alignment (8)
  3. Movement efficiency: Research shows concurrent training improves running and cycling economy in endurance athletes like runners, cyclists, and triathletes (8, 9), saving your energy and fuel for longer and harder sessions for enhanced endurance performance.
  4. Overall health: A combination of aerobic and resistance training is associated with a lower risk of all-cause mortality (10), so carving out time for both cardio and strength may boost longevity.
  5. Body composition: One study found that a concurrent aerobic and strength training program improved upper and lower body maximal strength and showed superior results in body fat loss compared to cardio or strength alone (11)
  6. Time efficiency: Squeezing all your workouts into a busy lifestyle can be challenging. Strategically planning your routine with concurrent training can get the same results in less time. 

With concurrent training, you get the best of both worlds—power and efficiency boosts from resistance exercise and heart and mental health benefits from cardio exercise. 

Designing a Concurrent Training Program

Strategically designing your program can help you reap the benefits of both without the potentially negative effects of concurrent training. Here are just a few ways to manipulate your resistance exercise with aerobic exercise to optimize your strength gains and aerobic capacity at the same time: 

  1. Alternate-day workouts: If your schedule allows, studies show that performing strength and cardio sessions on different days maximizes your muscular strength, muscle size, and endurance performance (3). That way, your body has time to recover and adapt to the specific challenge of each workout. 
  2. Goal-forward workouts: Frontload your main exercise goals at the beginning of the workout. For example, if you’re trying to get stronger in your deadlift, program that exercise first following your warm-up and hold off on your cardio until later in the workout. Similarly, if you’re training for an upcoming race, running first will ensure you’re fresher and have more fuel (like carbohydrates) at the start of your workout. 
  3. Strength-focused workouts: If you’re aiming for muscle growth or strength development, studies support focusing on resistance exercise first before doing cardio (12)
  4. Pair running with upper body strength and cycling with lower body strength: There is evidence that eccentric forces in running may have more of an inhibitory effect on muscle protein synthesis than cycling, and upper body strength is often not affected by endurance training (13). Alternating muscle groups in your strength and cardio exercise creates a more balanced routine.
  5. Align intensities: The molecular changes in skeletal muscle depend on intensity. High-intensity weightlifting or power exercises pair well with high-intensity cardio intervals, like high-intensity interval training (HIIT), because they use the same energy system. Similarly, low-intensity lifts may pair well with long, slow-duration cardio (like Zone 2). 
  6. Don’t sweat it: Consistency is more important than exercise order if you're just starting out. Enjoying your exercise sessions is a strong predictor of long-term engagement in physical activity (14).

How to Program Concurrent Workouts Based on Your Goal

Fitness or Workout Goal Recommended Sequence or Pairing
Improve maximal strength or hypertrophy Strength then Cardio
Improve cardiovascular endurance or aerobic capacity Cardio then Strength
Hybrid athlete (goals set for strength and endurance)  Alternating strength and endurance days (or provide plenty of time in between to rest and refuel)
General fitness (high-intensity workout) Heavy resistance training + HIIT cardio
General fitness (low-intensity workout) Light resistance training + Zone 2 cardio 
General fitness (upper body strength day) Upper body resistance training + Running for cardio
General fitness (lower body strength day) Lower body resistance training + Cycling for cardio
General fitness (novice exerciser) Focus on consistency over programming order

Nutrition and Recovery in Concurrent Training

Nutrition can play an imperative role in the adaptive responses to training. The availability of muscle glycogen, as a result of carbohydrate ingestion, absorption, and storage, and essential amino acids can stimulate the anabolic response in protein synthesis after strength training and facilitate ATP production (3)

Manipulating nutritional variables within a specific anabolic window may be an easy way to attenuate the potential adverse effects of endurance training on protein synthesis. Studies show a positive relationship between protein and carbohydrate ingestion with metabolic recovery in muscle damage and force production (15). Carbohydrate and protein ingestion is also tied to lower muscle damage and improved resistance training adaptation (16)

A positive energy balance with adequate carbohydrate and protein replenishment may address the interfering effects of endurance training. Low energy availability (not eating enough) is related to higher AMPK levels (3), which can down-regulate muscle protein synthesis. Aim to take in as many calories, if not more, than you burn when performing a high volume of strength and endurance exercise. 

In addition to dialing in your nutrition, there are a variety of recovery techniques to support your training. Getting adequate sleep and managing hydration and stress are crucial to perform your best and avoid overtraining when training volume is high.

Conclusion

Concurrent training is the basis of all health-promoting exercise recommendations: combining strength and cardiovascular exercise is the pathway to enhanced performance and longevity. Some research indicates endurance exercise may interfere with your strength- and muscle-building capacity due to fatigue, energy depletion, or competing molecular responses.  

There are science-backed ways to design your training program to avoid interference effects. Opt for alternating days if you’re training at high volumes in both strength and endurance. Combined in one workout, match the exercise order to your goals—you’ll be fresher and fuelled for the exercise you perform first. Recovery strategies and nutrition help to support concurrent training, so embrace your downtime with as much vigor as your workouts.

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Concurrent Training FAQs

What is a concurrent training model?

Concurrent training combines resistance and aerobic training within a workout plan. Sometimes called hybrid training, this protocol can include both forms of exercise within a week or a single session.

What is an example of concurrent exercise?

A concurrent training workout may look like heavy weightlifting paired with HIIT on a bike, an upper body strength workout paired with a long cycle workout, or alternating daily total body strength and endurance training based on your specific training goals.

What are the benefits of concurrent training?

Concurrent training builds your movement efficiency, overall function, and quality of life. Performing both strength and cardio in your routine improves physical and mental health, longevity, and athletic performance.

  1. Physical Activity Guidelines for Americans
  2. Interference of strength development by simultaneously training for strength and endurance
  3. Interference between concurrent resistance and endurance exercise: molecular bases and the role of individual training variables
  4. Concurrent training: a meta-analysis examining interference of aerobic and resistance exercises
  5. Concurrent strength and endurance training: from molecules to man
  6. The Relationship Between Maximal Strength and Reactive Strength
  7. Injury Prevention, Safe Training Techniques, Rehabilitation, and Return to Sport in Trail Runners
  8. Resistance Exercise for Improving Running Economy and Running Biomechanics and Decreasing Running-Related Injury Risk: A Narrative Review
  9. Strength Training Improves Exercise Economy in Triathletes During a Simulated Triathlon
  10. Prospective Associations of Different Combinations of Aerobic and Muscle-Strengthening Activity With All-Cause, Cardiovascular, and Cancer Mortality
  11. Effects of resistance, endurance, and concurrent exercise on training outcomes in men
  12. Acute Effect of High-Intensity Aerobic Exercise Performed on Treadmill and Cycle Ergometer on Strength Performance
  13. Concurrent training: a meta-analysis examining interference of aerobic and resistance exercises
  14. Exploring the impact of individualized pleasure-oriented exercise sessions in a health club setting: Protocol for a randomized controlled trial
  15. The influence of carbohydrate-protein co-ingestion following endurance exercise on myofibrillar and mitochondrial protein synthesis
  16. The effect of a carbohydrate and protein supplement on resistance exercise performance, hormonal response, and muscle damage
Contents
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Cite this page:

Reiner, S. “A Science-Backed Guide to Building Aerobic Capacity and Muscular Strength” AIM7.com, March 1, 2024, www.aim7.com/exercise/resistance-training/concurrent

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