Bodybuilding veteran Scott Abel has a radical plan to turn arm day into the best fat-burning workout of the week.

If you do traditional body-part training, you probably have an "arm day in your routine. But there's a problem with arm day: You may get some muscle-building response in the muscles you're targeting, but there's hardly any metabolic effect. In terms of conditioning, arm day is pretty much a day off for your body.

Here's why that's an issue: Neural drive — your body's ability to recruit the largest and most powerful motor units — is actually stronger during a fatiguing workout. This not only increases your ability to overcome fatigue, it makes targeted training to specific muscles even more effective.

Let me say that again because it's unlikely you've heard it before: When you train to recruit high-threshold motor units in a fatigued state, you achieve better neural drive and more efficient overload.

Good news for hard-gainers and hard trainers, bad news for the lazy types.

The following workouts combine total-body conditioning, core and movement work, and pure arm training. It's meant to fit into a traditional five-day body-part split — three days on, one day off, two days on, one day off. I often use this kind of arm training with bodybuilders who're peaking for a show. If we do it early in the dieting stage, it enhances metabolic response, allowing them to get leaner faster, with less calorie reduction and while retaining more muscle mass.

You can do either of these workouts on arm day, or alternate them from one week to the next. Just make sure you always do your arm training on the same day. And be prepared — this one will knock you on your ass if you aren't ready for it.

Workout 1

Do two warm-up sets of the first exercise.
1A) Barbell walking cheat curls
Sets/reps: 6 x 8-10

1B) Alternating chopper sit ups
Sets/reps: 6 x 10-15 (each side)

2A) Alternating dumbbell biceps curls
Sets/reps: 4 x 8-10 (each arm)
2B) Dumbbell alternating plank pull-ins
Sets/reps: 4 x 10-12 (each side)

3A) Machine preacher curls
Sets/reps: 4 x 10-12
3B) Rocky abs
Sets/reps: 4 x max

4A) One-arm Zottman curls
Sets/reps: 3 x 12-15 (each arm)

4B) Elevated medicine-ball plank holds
Sets/reps: 3 x slow count to 30

5A) Machine triceps dips
Sets/reps: 4 x 8-10
5B Alternating lunges with front reach
Sets/reps: 4 x 10-15 (each leg)

6A) Cable overhead rope extensions
Sets/reps: 4 x 10-15
6B) Alternating lateral lunges with reach
Sets/reps: 4 x 10-15 (each leg)

7A) Cable one-arm triceps pushdowns
Sets/reps: 4 x 10-15 (each arm)
7B) Alternating lunges to rear with reach
Sets/reps: 4 x 10-15 (each side)

8A) Cable reverse-grip one-arm pushdowns
Sets/reps: 4 x 15 (each arm)
8B) Dumbbell overhead lockout holds
Sets/reps: 4 x slow count to 30

You'll notice that the core and conditioning exercises become more fatiguing as you move through the workout, while the triceps movements become more targeted and isolated. The goal is to take advantage of the fatigue while increasing neural drive to the arms.

On the conditioning exercises — the functional movements — you make progress three different ways. First, increase the speed of your movement. Second, increase the range of motion. Third, add more weight.

Workout 2

Do two warm-up sets of the first exercise.

1A) Standing barbell curls
Sets/reps: 6 x 8-10
1B) Diamond push-ups, hands on medicine ball, elbows wide
Sets/reps: 6 x 10-max

1C) Medicine-ball vertical choppers
Sets/reps: 6 x 10-15

2A) Dumbbell one-arm preacher curls
Sets/reps: 4 x 8-10 (each arm)
2B) Reverse triceps push-ups (fingers turned outward), feet on Swiss ball
Sets/reps: 4 x 10-15

2C) Swiss-ball step-offs
Sets/reps: 4 x 10-15 (each leg)

3A) Standing overhead curls, with tubing or cable
Sets/reps: 4 x 10-15

3B) Swiss-ball plyometric impact push-up, hands close together
Sets/reps: 4 x 10-15

3C) Barbell wide rotations
Sets/reps: 4 x 10 (each side)

4A) Alternating hammer curls
Sets/reps: 4 x 10-12 (each arm)
4B) Alternating sit-ups off Bosu ball, elbow to knee
Sets/reps: 4 x max (each side)

5A) Lying triceps extensions (barbell or dumbbells)
Sets/reps: 4 x 6-8
5B) Dumbbell alternating lunges with front reach, from step
Sets/reps: 4 x 10-15 (each side)

6A) Dumbbell one-arm triceps extensions on Swiss ball
Sets/reps: 4 x 8-10 (each arm)
6B) Dumbbell alternating lunges with posterior reach and upright row
Sets/reps: 4 x 10-15 (each side)

7A) Cable overhead rope extensions
Sets/reps: 4 x 12-15
7B) Dumbbell alternating lateral lunges with reach and press
Sets/reps: 4 x 12-15 (each side)

If you're wondering why I switched from trisets (A, B, and C exercises) to traditional supersets (A and B exercises only), it's because the metabolic exercises toward the end of the workout include extra movements, like a row or press. That takes the place of the third exercise.

No matter how many exercises are included in each complex, try to move as quickly as you can from one to the next. When you finish all the exercises in the triset or superset, monitor your breathing to decide when to begin the next one. You want to remain in a noticeably fatigued state throughout the training session, which should last about 70 to 85 minutes.

How fatigued you get, and how fatigued you remain during the workout, will vary from week to week. Pay attention to your body and follow the cues it gives you. On days when it's just not there, you need to dial it back a bit. Otherwise, dial it up by moving faster between exercises, taking less recovery between sets, and progressing on the metabolic exercises as I described.

I call this "keeping it alive" — the more carefully you listen to your body and abide by its instructions, the more you'll get out of your programs in the long term.