How to mix strength training and HIIT in the same program

Your progress with some types of training can be hindered when paired alongside their opposing type of training. On one side of the spectrum there are performance-specific sports where athletes spend most of their time on the court or track, like basketball and running. If an endurance athlete’s goal is to run a marathon in two hours, none to negligible time should be spent lifting heavy weights. On the other side, there are strength-specific sports where training is spent almost entirely in the gym, such as powerlifting and Olympic lifting. If an individual only desires to increase strength or improve muscle mass, cardio should not be implemented in their program.

Most people’s motives to train fall somewhere in the middle of these and should see a wide variety in their training, striving for overall improvement. There are strategies that can be implemented where we can simultaneously include both resistance training and endurance training in the same program, known as concurrent training, and still get positive adaptations. I will describe what those are by reviewing studies and their results, followed by an application section so you can apply this to your routine.

Let’s describe the studies:

A.) Study 1. Group 1: resistance training only. Group 2: resistance training with HIIT where the sessions were separated in two parts- HIIT session in the morning, strength session in the evening with a rest period of 7 hours in between.

B.) Study 2. Group 1: resistance training only. Group 2: resistance training with HIIT in the same session. Group 3: resistance training separate from HIIT with 6 hours rest in between. Group 4: resistance training performed 24 hours after HIIT session.

Findings:

In the first study, the group performing resistance training only did not run into concurrent adaptations and increased their 1 rep max (bench press and squat) by a significant marker. Interestingly, it was noticed that similar strength adaptations were achieved in group 2. It appears that by allowing a minimum of 6 hours between sessions the body was able to adapt to the stimuli imposed and not run into conflicting adaptations from the opposing modalities.

The second study found similar net gains from the group performing resistance training only, correlating to previous findings. It was documented that in groups 3 and 4, strength increases were similar across the board with a slight positive inclination towards 24 hours in between sessions. As for group 2, the findings were quite different. By having resistance training and HIIT mixed in the same sessions, strength did not increase significantly when compared to resistance only groups.

This is important information because now we can make strategic decisions to optimize your training program. If the primary goal is to increase strength and muscle, keep your HIIT training sessions 6-24 hours apart from your resistance training. However, if mixing modalities in the same session to save time, preferably allocate HIIT with upper body resistance training. Avoid mixing HIIT with lower body strength days due to hindrance of force production and fatigue setting in.

Enjoy, friends! Let me know if have any questions.

Alejandro

References:

Study 1: Balabinis et al

Study 2: Robineau et al