1 Frequency of muscle groups worked

If currently working each muscle group more than once a week, change to only once over the seven-day period. Drive up intensity though, so that the muscles are exhausted at the end of the session. A punishing leg routine can require a whole week for the legs to recover.

2 Sets

Experiment with altering routines for stubborn muscle groups. Perhaps some sets should be eliminated, or rest time in between strenuous sets should be increased.

3 Reps

Has the same rep-range max been used for too long? If it’s six, try adjusting the weight so 10 reps can be pumped out. If it’s 10, go heavier so only six can be done. Be variable.

4 Sequence of routines

On leg day, for instance, do squats always come first? Do leg workouts always finish with hamstrings? Though the general rule is to work the entire leg before its segments, a plateau is a good reason for bending this rule. Try doing
leg extensions first, and then hit the squats. Apply this principle to other muscle groups.

5 Time of day

If the body is used to working out in the evening, shock it by lifting weights early in the morning, or vice versa.

6 Workout days

Is back always worked out on Monday, legs on Wednesday, and arms on Friday? Shuffle things up to “confuse” the body.

7 Muscle group combos

Switch ‘em up. If triceps are normally done with chest, and biceps with back, change to a chest-biceps and a back-triceps combination.

8 Equipment

Is the same apparatus always used for shoulders? Change machines; most large gyms have at least a half-dozen apparatus for each muscle group. If mostly machines are used, substitute free weights for some of the apparatus routines. If mostly free weights are used, try some selectorized equipment (machines with weight stacks that
use a pin to choose the weight used).

Okay, these first eight are fairly simple to implement. Next
comes some fancier stuff.

9 Supersets sets

Do two sets consecutively of opposing muscle groups (supersets). Example: Bench press, lat pull-down, then rest. Or triceps push-down, barbell biceps curl, then rest. Or apply this drill to the same muscle group (compound sets). Example: Lat pullover, seated row, then rest. You may even do three consecutive sets: Barbell leg presses, hack squats, leg extensions—then rest. Rest time will be
longer--up to three to five minutes, depending on intensity and muscle groups worked. Go for unique combinations as well: Seated chest press, then lateral raises with dumbbells.

10 Drop-sets

These involve one muscle group at a time. Perform a desired rep max, then immediately lower the weight enough to be able to repeat the same number of reps. Go promptly a third time. Then rest. Example: Incline dumbbell press: 8 x 90; 10 x 70; 20 x 25.

11 Partial reps

Military press machine example: Rather than pushing the weight all the up with to where the arms are straight, stop a little more than half way (keeping arms bent). Do all reps this way. Pullover example: Rather than let the bar go all the way up, which straightens the arms, let it go only half or 3/4 of the way up before pulling it back down.

12 Isometric reps

Lateral dumbbell lift (shoulder abduction) example: When the weights reach their peak height out to the sides, hold them there for 2-3 seconds, then lower with control. Lighter weights will be needed to be able to perform the same number of reps typically done.

13 Stage reps

This can be done during the positive or negative phase. Chest press example (positive): Push weight out one-third of the way and pause; resume to 3/4 of the way out and pause; then push out all the way out. Release normally. Do all reps this way. Prone hamstring curl example (negative): As the weight is lowered, pause midway, then resume lowering it.

14 Negative training

Slow the negative portion of reps down. Yes, it hurts to high heaven, but it’s a real shocker to the body. Leg extension example: Rather than let the legs fall back down, take 8-10 seconds to lower the weight. If this can’t be done the weight is too heavy. Lateral dumbbell lift example: While maintaining crisp form, take 5-7 seconds to lower the weights back to the sides.

15 Pyramids

These are reverse drop-sets. Preacher curl example: 12 x 30; 8 x 50; 6 x 70

16 Angles

Is a wide grip always used on a rowing apparatus? Switch to a narrow grip. Or vice versa. Some selectorized machines have multiple handles. Don’t always use the same ones. Change palm positioning when using dumbbells. Incline dumbbell press example: If palms are always facing each other, face them forward so the thumbs are facing each other. Pullover example: If palms always face away, grab the bar so that they’re facing in. Seated hamstring curl example: turn the feet outward as far as possible, which will force the legs to turn outward. Squat example: Place feet closer together, or further apart than usual. And/or point feet outward.

17 Attachments

Is the same hand piece used for triceps pull-downs, rows or pullovers -- even though the plastic box near the equipment has a dozen different attachments? Use ones never tried before.

18 Forced negatives

For unilateral routines, such as cable shoulder raises and dumbbell preacher curls, a partner isn’t needed. Dumbbell preacher curl example: After curling up the weight, hold it there. Then grab the wrist with the free hand and—while trying to keep the weight up, pull the wrist away to oppose the action. The opposing force will eventually win. A partner can provide opposing force during negatives for other routines such as barbell and apparatus exercises.

19 Assisted training

This requires a partner. When muscle failure is reached, a partner can provide just enough assistance to help with the positive phase then the negative can be done solo in a controlled manner.
Once enough strength is lost to where the negative is also too much to control alone, a trainer can add just enough help to enable carrying out the task
until muscles are completely failed.

And if you dare
Combine some of these techniques. For instance, drop-sets, partial reps and isometric reps can be incorporated all in one heap. Or supersets and negative training can be consolidated.