You’ve got a regular workout schedule that you’ve been meeting routinely, but you’re in need of some structure to your workouts. The following is a four-week plan that you can follow if you’re looking to gain muscle mass.

The week is broken down into four days. The total workout time should be 55-65 minutes. Take 5 minutes to do a dynamic warm up to get your body loose. Also, be sure to do 3-5 warm-up sets with lighter weight on your main exercise (the first one) and progressing to your working sets – this should take another 10 minutes. Also at the end of your session feel free to do whatever core work you like for 5 minutes. On off days go for a walk, hike, or do some stretching; but nothing intense as you need to recover.

Each week, start at the higher end of the rep range and as you progress, increase your weight and reduce your reps by 1-2 so that in week 4 you are handling the heaviest hypertrophy loads. Working sets on your main lifts should be done at an RPE (Rate of Perceived Exertion) of 7.5 or 8.

Back Squat - 3 - sets x 6-10 reps

Sumo Deadlift - 3 sets x 6-10 reps
3 minutes rest between sets

Dumbbell Split Squats - 3 sets x 10 reps
2 minutes rest

Leg Curls - 3 sets x 8-10 reps
90 seconds rest

Back Extensions - 3 sets x 15-20 reps
60 seconds rest

1000 metres on a rowing machine

Day 2
Push Press - 3 sets x 5-8 reps
3 minutes rest

Chin ups – 5 sets x 5 reps (add weight if bodyweight is too easy)
2 minutes rest

Close Grip Pull-downs - 3 sets x 8-10 reps
Attach a long bar to a cable machine where you sit with a support over your quads. Grip underhand, just inside shoulder width apart. Pull the bar to your chest while maintaining your posture, slightly leaning back. Keep your back straight through the whole motion. 
90 seconds rest

Triceps Pushdowns - 3 sets x 15-20 reps
Bicep Curls - 3 sets x 6-10 reps
90 seconds rest

Day 3
Front Squat - 5 sets x 5 reps
Deadlift 7 x 5 reps at 50% of 1RM
3 minutes rest between sets

Barbell Hip Thrusts - 3 sets x 10-15 reps
To perform these, use a bar pad or wrap a towel around the middle of the bar to prevent the barbell from digging into your hips. Place your upper back on the bench, barbell across your hips. Ensure that your feet are firmly planted as you thrust your hips up.
2 Minutes rest

Banded Kettlebell swings - 5 sets x 1 minute of work
Place a band just above the knee for this move

Day 4
Bench Press - 3 sets x 6-10 reps
3 minutes rest between sets

Incline Dumbbell Press - 3 sets x 12-15 reps
2 minutes rest between sets

5-1-2 Tempo Push-ups - 3 sets x 12-15 reps
5 seconds down, 1 second at the bottom and 2 seconds on the way up
2 minutes rest between sets

Dumbbell Rows - 3 sets x 12-15 reps
2 minutes rest between sets

Banded Pull Apart - 3 sets x 30 reps
30-60 seconds rest

Suitcase carry with Kettlebell or dumbbell - 40 yards each hand x 3 rounds - no rest
Sled/prowler push - 3 laps - 60 seconds rest between laps