A lot of people worry about overtraining, but it's better to overtrain than to sit on your couch and give in to the deathly hallows of obesity. Kirk Miller is a Grenade athlete intent on ridding the world of the out-of-shape nonsense that plagues this planet.

He lifts six days each week, pounding his body with dropsets and mobility training. This effort guarantees his physical aptitude and sets a remarkable example for his clients. Try this workout and get introduced to dropsets, hulking hypertrophy, and serious strength gains.

Six days of training each week seems like a lot, but Kirk advises you to never carve your training regimen in stone. This is just a workout scheme he sometimes uses. Above all, you should listen to your body and train at a level it can handle. If you get tired, take a rest day. If a body part is lagging or you don't get the response you desire, then change it!

"I always like to keep the body guessing," Miller says. "No workout is ever the same. A lot of the time that is for a number of reasons. I am too busy to wait at the gym. I'm never an advocate for waiting 10 minutes to get on the machine for the workout I wrote."

If someone is talking on their cell in the squat rack, then adapt and survive. Don't get mad, just suck it up and adjust your plan. If you prepare yourself with options, you'll never run out of exercises in the gym.

Kirk's Split

If a certain muscle isn't growing the way I want it to grow, then I do something different.

• Day 1: Chest and Cardio
• Day 2: Back
• Day 3: Hams, Calves and Cardio
• Day 4: Shoulders and Abs
• Day 5: Biceps, Triceps and Cardio
• Day 6: Quads and Calves
• Day 7: Rest

Generally, Kirk only takes the one rest day per week. He often scales back his HIIT cardio to conserve energy for the lifting sessions. His HIIT sessions last from 10-15 minutes up to twice per week. If you take a day off lifting, try this brief cardio kick to keep improving.

"If you have a sticky point in your training, or a body part that doesn't feel right, then change it," Kirk says. "Why overcomplicate things? People will keep bashing away at this same routine or the same amount of rep ranges. If I feel that a certain muscle isn't growing the way I want it to grow, then I do something different."

Kirk's Training Regimen

These are the basic guidelines for Kirk's workouts. He varies his workouts, so swap exercises and rep ranges depending on how you feel. This is a guideline to work from.

Day 7: Rest

Royal Marine Challenge Exercises

To get ready for the Royal Marine Challenge, Kirk added a few unique twists on classic moves to prepare his body for the intense training of the military elite. Hit all of these exercises consecutively and try to walk!

Your legs are going to be so heavy, you're going to want to give up. Just push yourself hard until you are officially shot. This workout incorporates your fast-twitch and slow-twitch fibers, and engages both your aerobic and anaerobic capacity.

Note: Use a moderately heavy weight for the resistance exercises and take each one to failure. Hit the treadmill and step mill for 15 minutes each.

1. Negative Leg Extensions

With help from a spotter, these pre-fatigue your quads, making your legs burn out from the workout.

2. Paramount Squats

The unorthodox position of the machine facilitates a deep burn within the quadriceps.

3. Walking Dumbbell Lunges

This mimics the heavy armor you carry in the Marine workout. The more tired you get, the more your balance is tested. It affects concentration.

4. Mini Plyometric Circuit

Jump over a box, go straight into a press-up, then into chin-ups. Incorporate your entire body with three simple exercises.

5. Double Cardio

Perform treadmill interval sprints to mimic the different paces you run, walk, or crawl during the assault course. Then hit the Stairmaster, which typifies the style of cardio you incorporate for Marine-style workouts.