Here's what you need to know...

1. Don't fatigue your core between strength movements. Leave ab work for the end of the workout.
2. Take your height and weight into consideration when doing metcon workouts.
3. After doing a strength workout for one lift, anything else done in the name of strength training defaults to conditioning.
4. Some supersets do more harm than good. Pairing exercises that apply the same forces on the spine is a recipe for disaster.
5. You can't train multiple attributes (strength, mobility, conditioning, etc.) at the same time. Choose one goal and attack it.

1. You're Doing Abs Mid-Workout

Direct core training is a classic go-to "interlude" exercise to do as a filler between sets of a barbell movement, or between two barbell exercises.

Even if you've learned to ditch the sit-ups and bicycle crunches and the ab exercise you're doing is sophisticated and targets your weaknesses, when you do them is what's most important.

Remember, workouts break muscles down and ultimately leave them in a state of fatigue. That's the last thing we want to do to our core in between some of the most core-dependant movements in the gym.

Stop cracking out sets of hanging leg raises between sets of your deadlifts or squats. Even if you don't feel your performance slipping while you do, know that you're in a better position by keeping them separate. Again, it's wise to let paired exercise selections assist one another in their proficiency.

The lesson: Leave ab work for the tail-end of a workout.

2. You're Using Dumb Supersets

Some superset choices cause more harm than good. Pairing exercises that apply the same forces on the spine or other load-bearing joints can be bad news, especially if you have a history of (or propensity towards) injury to those regions.

For example, back squats and barbell overhead presses both put compressive forces on the spine, so supersetting them isn't too smart. It may not sound like a big deal, but after 4 or 5 rounds your lumbar spine may be telling a different tale.

Instead, use supersets that allow one exercise to positively affect the performance of the other, and vice versa. If you're doing barbell presses, supersetting them with pull-ups or pulldowns is a smarter move because vertical pulls apply traction and decompressive force to the spine, along with stabilizing the scapulae, which can improve stability when doing presses on subsequent sets.

The lesson: Think twice before pairing any two movements together. Think of how those movements act on your skeleton.

3. You're Not Factoring in Height and Weight for Metcon

I have a love-hate relationship with any "reps-for-time" challenges. I recently did a two-minute bodyweight squat challenge. I just loaded the bar up with 250 pounds and did as many squats as I could in two minutes.

Needless to say, this floored me. Literally. Looking back, however, it's clear that I'm at a disadvantage compared to many other people of differing body types but similar strength ratios.

Put me (a 6'4" lifter) against a short dude squatting his bodyweight equivalent and I'll guarantee he'll perform more reps, simply because each rep will eat up less time for him than it would for me.

But this goes further. Many "metabolic conditioning" workouts will have aggressive demands on rest intervals when compared to training volume.

By all means, if your body can handle it, go to town, but an in-shape, well-conditioned 6'4" 260-pound lifter will have a harder time with 30-second rest intervals than an in-shape, well-conditioned 5'9" 175-pound lifter.

It's simply asking too much of a larger person to expect him to keep up with such parameters without taking his size into consideration.

Programs like German Volume Training also require a close watch to find the "sweet spot" where the amount of weight lifted depends on the weight and size of the lifter, so that adequate fatigue can be reached without reducing the weight too substantially. Bigger guys should stay closer to the 60-65% range and smaller guys can live in the 70% range.

The lesson: Take your height and weight into consideration when doing metabolic conditioning workouts. You'll still get the same training effect without running yourself into the ER. And, if you're a tall guy doing a challenge, know that short guys will probably beat you. Use it for the conditioning and have fun!

4. You're Overusing Correctives

"Correctives" are all those trendy exercises and techniques designed to fix your posture and correct imbalances or movement patterns.

That's fine, but corrective exercises should supplement your program, not dominate it. If you want to see results, you need to actually lift for the majority of your workout and not eat up your entire gym time doing preventative maintenance.

As a general rule, choose one corrective focal area per workout to address, and perform no more than two exercises for it. That keeps your attention focused on the meat and potatoes.

Too often, corrective exercises are a great way to tell all-around weak people they shouldn't practice the difficult movement that gives them trouble. Make sure you're not bad at an exercise simply because you don't do it often enough. Correctives are worthless if they don't have any carryover to the movement they're supposed to correct.

The lesson: Prioritize the big stuff. Nobody is in "perfect balance" and never will be. Address your weak links, but don't let it override what's important.

5. You're Strength Training More Than One Movement

If you talk to powerlifters, you'll note they all train in a way that emphasizes one lift per workout. Their goal in strength workouts is to amp their CNS up so they can perform as efficiently as possible when producing a max effort, hopefully resulting in a PR.

That's when speed work, paused rep work, and other advanced lifting methods come in handy for their programming. Accessory movements usually make up the remainder of a given workout in order to address weak links and muscle groups that may be stalling performance.

Let's apply this logic to a recreational advanced lifter who isn't a powerlifter, but wants to get stronger all the same. Doing a solid 8x3 workout on the strict press or deadlift is a great start and provides plenty of motor unit-specific volume, especially when adding ramping sets to the mix.

But things take a turn for the worse if you try to repeat these near max efforts with a second big movement for the day. Not only will your focus and explosive energy be diminished due to CNS fatigue, but the weight you'll be lifting will probably drop substantially – possibly to a degree that's no longer ideal for strength training in terms of 1RM percentages.

After doing strength work for one lift, anything else done in the name of strength training immediately defaults to conditioning training.

The lesson: Stick with one exercise for strength training and either hit up assistance movements to follow or do higher reps for the other big movement you had scheduled.

There's nothing wrong with following an 8x3 deadlift workout with a few sets of 10-12 on the bench press. Your nervous system and performance will thank you.

6. You're Killing Your Grip Strength on Back Day

You can only lift as much as you can hold. At most gyms, you see a lot of lifters with their hands and arms strapped up like G-Unit. People often don't realize just how much grip strength is salvaged in the name of straps, and because of this, it enables them to perform consecutive exercises that would compromise grip strength any day of the week.

And I'm not even talking supersets. A set and rest workout comprised of deadlifts, pull-ups, seated rows, one-arm dumbbell rows, and face pulls sounds pretty awesome, but you've just done five pulls in a row and that will likely lower the quality of at least the last two exercises.

Not only that, but your forearms and hands will be giving you the finger in the last 30 minutes of your workout.

Size addicts need to think about isolation when it comes to back workouts, and the idea should be to allow nothing to detract from properly stimulating and/or breaking down back tissue on back day.

Straps allow leeway, but that brings things too far in the opposing direction. It's a better idea to lift raw whenever possible as it'll positively affect overall strength and neuromuscular connection. Lifting without straps can be more effective in developing size than trying to isolate with them.

With that said, the solution to your grip going to hell on back day would simply be to interspace back movements that aren't super grip-reliant between heavy pulling movements. Some possibilities:

• Pullovers
• Stiff-arm pulldowns
• Bent-over reverse flyes

The lesson: Chuck the straps and lift old school! You'll salvage your grip strength by taking a second look at your sequence of pulling exercises on back day.

7. You're Not Using Common Sense and Training Intuitively

For some, deviating from a set program is worse than unfriending someone on Facebook. In light of this fear, people put themselves through movements that cause pain, or stuff that just plain doesn't work well with their body.

At a certain point in his training journey, an experienced lifter will be able to determine what works for him and what doesn't. For example, I've noticed that prone hamstring curls don't suit me very well. Even the seated curl is a better alternative in preventing unwanted knee stress.

The point is, if you have musculoskeletal issues or just general weak points in your performance or your physique, there's nothing wrong with making a slight modification or two to a program to make sure you get the results you want while maintaining your safety while doing it.

Moreover, physiology varies from day to day. If you're not feeling "strong" on a day where you're scheduled for some heavy doubles, there's no harm in making them triples and dropping the weight by 5-10% for the day. You're still strength training.

The lesson: Stay aware of how you feel during your workout, your rate of perceived exertion (RPE), and be mindful of injuries or weak points from your training history.

A program isn't the same as a personal strength coach who knows you intimately, so use your discretion when following one.

8. You're Pulling a CrossFit

Your program has correctives for your weak links, pre-workout mobility every workout, a sprint day, an explosive plyometrics day, three strength days, three post-workout cardio days, and promises size increases due to cumulative volume.

That's the kind of program that will get you nowhere.

Trying to get results in everything will give you results in nothing. Proper training will always involve relative tradeoffs, and that's the truth.

If you want to train for size, you can bet your mobility will go down. If you want to train for strength, you can bet your conditioning and caridiorespiratory fitness will go down. If you're after mobility and athletic conditioning, you'll probably drop some size and maybe even some strength.

Olympic lifting? Say bye to tree trunks for arms compared to when you were bodybuilding training. You get the idea.

People who are professionals at their discipline would be training in various styles all the time if all elements of fitness could be tackled simultaneously. But they can't. The closest thing to that is called CrossFit, and I'll let you decide if that's worth it.

The lesson: Choose one goal at a time and attack it. The world will go on if you spend 6 or 8 weeks away from a given phase of training.