Climbing a flight of stairs may leave one short of breath, but lifting a heavy box shows a very different kind of challenge. This contrast, typically experienced by everyone, reflects the difference between resistance training and cardio. Both support health, but weight training is more effective for directly increasing muscular strength.

This blog shows the benefits of strength training, especially in how it differs from cardio. By the end, the blog will explore why weight training is the most effective path for greater muscular strength.

Defining the Key Terms

Before getting into it, it is important to understand the differences in mechanisms and effects between muscular strength and cardiorespiratory fitness.

Muscular strength

Muscular strength refers to how much force the muscles can produce when working against resistance. It is usually tested through the one-rep max (1RM), or the heaviest weight lifted in a single repetition. That is why strength improves once the muscles grow and the body learns to use them efficiently.

Cardiorespiratory fitness

Cardiorespiratory fitness measures the health of a person’s heart, lungs, blood vessels, and circulatory system. It is usually measured by VO₂ max, which shows how well the body uses oxygen. Remember that exercises like running, cycling, and swimming may build endurance, but they do not significantly increase maximum strength. In contrast, some peptides, such as Gonadorelin, have been explored for their role in hormone regulation, which can indirectly support recovery and training capacity.

How Weight Training Builds Muscular Strength

Weight training works by using progressive overload. This process actually sets off several of these changes in the body:

Muscle Hypertrophy
When muscles recover after lifting, tiny tears in the fibers heal and grow back stronger and bigger. This muscle hypertrophy process makes strength gains possible, and it has even been studied in relation to growth factors like IGF-1 LR3, which play a role in muscle repair and development.

Neuromuscular Adaptations

The nervous system also gets better at sending signals to the muscles. This improves coordination and allows more muscle fibers to work together and increase overall strength.

Hormonal Response

Weight training triggers a hormonal response, which raises growth hormone and testosterone levels. These hormones help the muscles recover and grow stronger.

Altogether, these explain why weight training is more effective for developing muscular strength than cardio alone.

Why Cardiorespiratory Fitness Improves Differently

Cardio training focuses on sustaining movement for extended periods. That is why it can strengthen the body in these ways:

• Cardio improves heart stroke volume and efficiency.
• It enhances oxygen delivery through increased capillarization.
• Cardio also boosts mitochondrial density for better energy production.

Although these changes build endurance and overall stamina, cardio does not apply enough mechanical load to the muscles. That is why it doesn’t trigger muscle hypertrophy or significantly increase maximum strength.

Key Scientific Studies/Research Evidence

A 2017 review in Sports Medicine found that resistance training increases muscle size and strength more than aerobic exercise. Meanwhile, another study in Medicine & Science in Sports & Exercise showed that strength training not only builds muscle but also improves bone density and metabolism.

Practical Training Recommendations

Weight Training 

The goal here is to build strength and muscle mass while improving overall performance.

Frequency: 2-4 sessions per week

Example Training Styles:

• Powerlifting: Heavy loads (80-95% of 1RM) with low reps (1-5) to maximize strength.
• Bodybuilding/Hypertrophy: Moderate loads (65-80% of 1RM), 6-12 reps to build size and strength.
• Circuit Training: Combines resistance and cardio for improved muscular endurance.

Cardiorespiratory Fitness

Cardiorespiratory training focuses on improving cardiovascular and pulmonary health to build stamina and aerobic capacity.

Frequency: 2-3 sessions per week

Example Training Styles:

• Steady-State Cardio: Running, cycling, or swimming at moderate intensity for 30–60 minutes.
• HIIT (High-Intensity Interval Training): Short bursts of intense activity followed by rest to support calorie burn and cardiovascular fitness.
• Tempo Runs/Threshold Training: A sustained and challenging pace to improve VO₂ max.

Concurrent Training 

This training plan combines the benefits of both strength and endurance work. The balance of both strength training and cardio may actually deliver well-rounded fitness.

Important guidelines to consider:

• Strength and cardio can be scheduled on separate days or as split sessions on the same day.
• In split sessions, perform weight training first and cardio second to keep muscular strength as the priority.
• Strength training: 2-3 sessions per week
• Cardio: 2 sessions per week, 20-40 minutes each

Common Misconceptions

Misconceptions about weight training, cardio, and their effects are often spread everywhere. Although they may sound convincing, they are not always supported by scientific evidence. Some may include:

• “Cardio kills your gains.”
  Research actually shows that moderate cardio, when paired with proper recovery and nutrition, does not prevent strength improvements.
• “Lifting weights is the same as cardio.”
  Fast-paced lifting may raise heart rate. However, it does not provide the same cardiovascular adaptations as sustained aerobic exercise. Cardio improves heart and lung efficiency in ways that weight training alone cannot.

• “Weight training alone is enough. Cardio isn’t necessary.”
  Weight training may build muscular and bone strength. However, cardio improves heart health, circulation, and endurance. That is why both are needed for long-term, balanced health.

Conclusion

Despite their differences, weight training builds muscular strength, which is the key to lasting power. Meanwhile, cardio supports endurance and heart health. In the end, a program that values strength and endurance offers the most complete approach to long-term fitness.

Frequently Asked Questions

Can cardio improve strength at all?

Yes, cardio improves muscular endurance and overall fitness. However, it’s not as effective for maximal strength gains.

How long does it take to see strength gains from weight training?

Most beginners see progress in 4-6 weeks, as the nervous system adapts first. This is then followed by muscle growth.

Is it better to do cardio or weights first?

If your main goal is strength, you must prioritize weight training first. Afterwards, you may follow it with cardio.

Can you build muscle and endurance at the same time?

Yes, through concurrent training. Although strength gains may be slightly slower if endurance work is excessive.