Do 15 reps per exercise. Repeat for four rounds with minimal rest between exercises.
Reverse Lunge
Stand upright with shoulders back and core tight. Step back with one leg, and lower your body until your rear knee nearly touches the floor and your front thigh is parallel to the floor. While keeping the heel of front leg pressed firmly on the ground, return to the starting position. Alternate sides each round.
Push-up
While keeping core engaged and back flat, position your hands a little outside shoulder-width apart. As you begin to lower toward the ground, your elbows should be at about a 45-degree angle to your body. Try to lower yourself enough that your elbows are in line with your shoulders. While keeping core tight and back flat, push up to the starting position. You should only go for the full range of motion if you have the mobility and strength to do it properly. If you would like to modify to reduce the load, use an elevated stable surface for your hands to perform the exercise.
Squat
Stand with feet a little wider than hip-width apart. Focus on keeping your entire foot pressed into the floor and pushing through the outside of each foot as you lower into your squat. Think about sitting back, as if you would sit in a chair. Your torso should lean forward slightly with chest high and shoulders back. When you start to rise from the bottom of your squat, actively push your knees out and focus on using your glutes to do the work.
Cross-body Mountain Climber
From plank position, keep core engaged, slowly lift one foot and bring one knee to opposite elbow. Pause and return to starting position. Alternate sides in a slow and controlled manner. Focus on maintaining neutral spine and bracing your core.