There are two types of injuries in weightlifting, acute and chronic. Acute injuries are defined as "failures of biological structures caused by forces greater than the stress limits of the healthy tissue," and are associated with sudden and overwhelming forces and faulty execution.

Chronic injuries are defined as "failures of biological structures caused by forces which are less than the stress limits of the structure, but where the structure has lost its normal resistance to withstand loads, typically because of repeated loading," and are associated with extensive repetition.

Most lifters have learned the hard way that rounding too much during a maximal deadlift will result in immediate low back injury. This is an example of an acute injury.

Preventing acute injuries largely involves discipline. Research has shown that even during maximal attempts, the best powerlifters don't allow their spines to fully flex when deadlifting, they don't lean forward excessively during squats, and they don't flare their elbows when benching. They've spent years mastering technique and building the discipline to maintain proper joint positioning under heavy loads.

Considering that many powerlifters perform maximal lifts year-round, their resistance to acute injuries is very impressive. However, these same powerlifters are quite prone to chronic injuries.

It simply goes with the territory. If you want to be your strongest in powerlifting, then you absolutely have to regularly perform the big three powerlifts – the squat, bench press, and deadlift.

Moreover, there will be times when powerlifters will be forced to train through pain and ignore the body's natural warning signals. In fact, most powerlifters spend their entire lifting careers ignoring these signals. This is why many of them require 30-45 minutes just to feel warmed-up sufficiently to squat or bench. Their soft-tissue health is far from ideal and they need considerable time to coax the body into receiving such heavy loads.

There's surmounting evidence detailing the link between genetics and soft-tissue related injuries such as those occurring in muscle, tendon, and ligaments.

Many factors influence the likelihood of soft-tissue injury, such as genetics (for example, genetic variations in genes encoding for a specific collagen type or other protein) and environmental factors (for example, exposure to mechanical load during training, nutritional factors, and exposure to drugs), but it's really the gene-environment interaction that you need to consider.

Genes aren't preprogrammed for life; they respond to environmental stimuli to encode gene-products necessary for survival, and they require activation to do their thing. This has led to the emerging field of study known as "epigenetics," which bridges the gap between nature and nurture.

You can have great "genetics" for soft-tissue strength, but over time still suffer from chronic injury due to poor training practices. Conversely, you can have poor "genetics" for soft-tissue strength, but prevent chronic injury due to intelligent training practices.

Every workout incurs considerable micro-damage to the tissues, and an optimally functioning soft-tissue system quickly repairs these damages. However, many lifters don't possess ideal soft-tissue genetics and therefore must be more careful than their more genetically gifted counterparts.

The way you train plays a huge role in the chemical response in your soft-tissues following a workout, and these responses accumulate month after month, year after year. When it comes to healthy joints, you want to engage in practices that allow for the proper release of rejuvenating chemicals and prevent the release of excessive degenerative chemicals. These practices include proper warm-up, training volume, frequency, form, and recovery practices, but a common overlooked factor is proper exercise selection.

What if I told you that you could never squat or bench press again? Do you think you could still keep most of your strength and muscularity by performing exercises such as loaded Bulgarian split squats and dumbbell bench presses?

When I performed extensive EMG experiments, I found that it's possible to receive similar levels of muscle activation with "joint-friendlier" exercises compared to their riskier counterparts.

Now that I've really delved into the study of Biomechanics, I realize that you can put just as much torque loading on the joints with safer variations as you can with heavy barbell lifts. And research is now showing that you can induce just as much of a hormonal response with safer variations, despite this hormonal response being largely overrated in the past couple of decades by strength training writers.

Chances are you're not a competitive powerlifter. If you enjoy training like a powerlifter and your body holds up just fine, then carry on. But if your body doesn't hold up from powerlifting-style training, you don't need to go this route.

You can train more intelligently and reach your goals, which are to gain strength and muscle mass. Remember, the lifter who's able to train pain-free year-in and year-out has a distinct advantage over the lifter who's constantly training through pain or working around injuries. If you're a brittle and frail lifter, then here are my training recommendations:

Stay in the 6-15 rep range for ideal soft-tissue health. No need to go any lower than six reps as you can get plenty strong while avoiding excessive stress on the tissues incurred from maximal loading. Don't go any higher than 15 reps as this wouldn't be very conducive to maximal strength and muscularity, despite being easy on the joints.

Train 2-4 days per week, spreading the sessions evenly over the week. This will allow for adequate recovery between sessions. Here are your options:

• Two full body workouts per week with at least 72 hours in between bouts.
• Three full body workouts per week with at least 48 hours in between bouts.
• Two lower body and two upper body workouts per week, alternating between lower and upper body for a total of four sessions spread out as evenly as possible throughout the week.

Now it's time for the meat of the article. Powerlifters are obviously going to be biased towards the three powerlifts, Olympic lifters towards squat and Oly variations, and bodybuilders towards their favorite exercises as well. The various camps will never agree upon best training practices for all lifters.

In this article, I'm relying upon the following criteria to determine what I consider to be the safest way to train effectively:

• Practical evidence. What I've learned through twenty years of lifting in commercial gyms and athletic training facilities, things I've learned through the dozens of training partners I've had over the years, and things I've learned as a strength coach and personal trainer.
• Biomechanical rationale. What I've learned during my study of biomechanics, physics, and functional anatomy.
• Evidence in the literature. What I've learned through reading research pertaining to strength training related injuries.

Some lifts involve more risk than others. For example, nearly every seasoned lifter I know has incurred an acute injury from heavy squats, bench presses, and deadlifts. Yet I've never seen anyone injure themselves with inverted rows or sled pushes.

The study of Biomechanics can provide mathematical support for safest training practices. It's possible to use inverse dynamics and modeling to calculate joint moments and forces as well as loading on the individual muscles, tendons, and ligaments.

Though the research is scarce concerning heavy strength training, the calculations in the studies I've seen tend to jive with what experienced lifters already know. For example, the greater the trunk lean in a squat and the greater the lower back rounding in a deadlift, the greater the sheer loading on the spine.

Finally, studies have been undertaken to determine injury risk in various joints with experienced lifters. For example, behind the neck presses and upright rows have been shown to be more injurious to the shoulder joint than other shoulder exercises.

With this knowledge in mind, here are the exercises I believe should be avoided as well as the exercises that should be employed by lifters who are prone to injury.

The exercises below are not the "joint-friendliest" of movements. These exercises are responsible for most of the weight room injuries and should therefore be avoided by lifters who are prone to injury.

Below is a list of exercises that can safely be used by the majority of lifters over the long haul. There are seven categories of exercises, and each category includes my top three picks.

The caveat is that the exercises have to be "manly" lifts – no sissy exercises are allowed. These exercises will still allow for tremendous strength and size gains, with much less risk compared to more traditional methods.

Knee Dominant Exercise

All types of squats are risky for injury-prone lifters. Any time the envelope is pushed in terms of progressive overload in squat patterns, pain/injury tends to seep in.

Front squats are safer than back squats due to reduced forward trunk lean and bending moment on the lumbar spine, and goblet squats are especially safe for less advanced lifters.

Dynamic effort box squats are reasonably safe, but heavy bilateral squat variations are unnecessary. So are many bodybuilding exercises for the quads, such as the leg press (too risky for the low back) and hack squat (too risky for the knees). Finally, jump squats and Oly lifts are just too risky for various joints such as the knees, low back, and wrists.

Instead, single-leg knee dominant exercises can safely be employed in place of bilateral variations. With single-leg exercises, you can get identical knee and hip torque loading, equal knee and hip extensor EMG activation, and similar Testosterone release, with less compressive and shear loading on the spine.

For this reason the deficit reverse lunge, Bulgarian split squat, and skater squat are recommended.

• With the deficit reverse lunge, make sure you take an adequate rearward step. Feel free to use a considerable forward trunk lean, which works more glute and takes some stress off the knees.
• With the Bulgarian split squat, try to keep most of the weight on the front leg and make sure the knee tracks properly over the toes.
• With the skater squat, initially you can hold onto 10-pound dumbbells and perform a front raise during the movement which decreases knee joint loading while increasing hip joint loading (often referred to as a counterbalance). In time you can hold onto heavier dumbbells and keep them at your sides.

Hip Dominant Exercise

All deadlift and good morning exercises are too risky for brittle lifters, even hex bar deadlifts. Since the most torque loading on the joints is at the bottom of the lift, you get considerable shear and compressive forces on the spine, and the tendency to round when loads get heavy is too intense. Sumo deadlifts incur slightly less spinal loading than conventional deadlifts, and dynamic effort pulls are relatively safe, but all deadlift variations are a bit too risky.

Reverse hypers are usually performed incorrectly with too much lumbar flexion at the bottom of the lift, and many people feel discomfort along the posterior chain when performing the movement.

Glute ham raises are very safe – though most lifters use too much lumbar extension and anterior pelvic tilt during the movement, but they're not hip dominant so they don't fit properly into any of the seven categories. Many traditional strongman exercises place way too much loading on the spine and are therefore too risky.

Instead of bilateral deadlifts, single-leg RDL's can be performed safely with the majority of lifters. It takes some getting used to, but as you gain coordination you'll find the lift to be highly productive.

I've never seen anyone injure themselves with barbell hip thrusts or 45-degree hypers, even when form wasn't so stellar. Torque loading is spread more evenly throughout the hip extension range of motion in these exercises, making them safer than deadlifts and good mornings – and if the weight is too heavy during these lifts, you simply won't lock out the lift. Form doesn't degrade on these lifts like they do during standing posterior chain exercises.

The single-leg RDL will strengthen the bottom portion of hip extension, the 45-degree hyper the mid-range of hip extension, and the hip thrust the top portion of hip extension, so you'll have what my buddy Nick Tumminello calls, "full spectrum hip strength."

• With the single-leg RDL, keep the back leg straight and in line with the torso and the neck in neutral. Sit back as you would in a bilateral RDL and squeeze the glute to lockout.
• With the barbell hip thrust, make sure you don't hyperextend the low back or allow the pelvis to anteriorly rotate as the movement rises.
• With the 45-degree hyper, lock the torso into position and move solely at the hips, raising the body with just the hamstrings and glutes.

Upper Push

Any barbell press just isn't worth the risk since the bar prevents the arms from moving through their natural motions. Among the various presses, the behind the neck press and guillotine press are the riskiest, whereas the floor press and close grip bench press with shoulder width grip and elbows tucked are the safest, but there are safer alternatives to any form of barbell pressing.

Dips and military presses are just too inherently dangerous for injury-prone lifters, as are plyo push-ups and bench throws. Finally, flies and skull crushers place too much stress on the joints at the bottom of the movement and also aren't worth the risk.

Instead, perform the weighted push-up, dumbbell bench press, and dumbbell incline press, all with a neutral grip. Dumbbells allow for much more natural arm motion compared to barbell pressing. The safest arm position is around a 45-degree angle relative to the torso, so a neutral grip will actually involve a 45-degree angle as well since the wrists should be in line with the upper arms.

• With the weighted push-up, hold onto dumbbells positioned on the ground as this is easier on the wrists. Maintain good core stability and don't allow the hips to sag. Wear a weight vest or have a partner stack plates on your upper back.
• With the dumbbell bench press, go deep, but not too deep, and remain very stable.
• With the dumbbell incline press, don't let the arms flare fully outward and control the tempo.

Upper Pull

Many traditional upper back exercises are just too risky. Bent over rows and T-bar rows encourage lumbar rounding and jerky movements. Most lifters can't maintain proper lumbopelvic position during seated rows and end up using too much momentum.

Even pull up and chin up variations can be problematic as they tend to beat up lifter's elbows and shoulders when going too heavy or going overboard on the volume. I know many lifters who have hurt themselves during chins/pull ups, but not one who hurt themselves with D-handle lat pulldowns. Same for inverted rows and one-arm rows; I've never seen an injury with these lifts.

Argue all you want, but pulling a cable down to your chest involves less unwanted joint stress compared to pulling your body up and over a stationary bar. Upper back exercises such as upright rows and pullovers involve too much joint stress and should therefore be avoided.

• With inverted rows, use a TRX, rings, or blast straps to allow for natural arm motion. Elevate the feet to increase the challenge.
• With the one-arm row, perform them under control. Kroc rows are popular, but avoid excessive momentum and rotary motion at the spine.
• With the lat pulldowns, use the D-handle and pull to the upper chest.

Core

There are optimal loading parameters for dynamic spinal exercises, with too much or too little volume being sub-optimal for maximum spinal health and longevity, although this is just a theory and is yet to be proven.

Though I believe that the dangers are grossly overrated, until more is known, it's best to err on the side of safety and stick to solely core stability exercises. So no crunches, sit ups, hanging leg raises, side bends, supermans, woodchops, or any other dynamic spinal exercises.

Ab wheel rollouts are also too risky; I know several lifters who felt like they tore their lower abdomen from this exercise. Sick with RKC planks, side planks, and Pallof presses.

• With RKC planks, make sure you squeeze your glutes hard to engage a posterior pelvic tilt. Drive the elbows toward the feet and the feet toward the elbows to increase the challenge.
• With the side plank, make sure you stay in a straight line. Elevate the feet to increase the challenge.
• With Pallof presses, get in an athletic stance and make sure you're symmetrical.

Functional Exercises

Nobody seems to hurt themself performing farmer's walks, pushing sleds, or swinging kettlebells. Though these exercises do place considerable loads on the spine, anecdotally they're well tolerated by the vast majority of lifters.

• With farmer's walks, start with the implements elevated so you don't have to bend over and pick them up. Maintain good posture while you walk.
• With sled pushes, hold proper posture and focus on good hip drive.
• With kettlebell swings, hinge at the hips and sit back, keeping the lumbar spine as neutral as possible.

Bodybuilding Accessory Lifts

Most lifters like to throw in some higher-rep pump work at the end of a session. While exercises like band triceps extensions, single-leg calf raises, straight-arm pulldowns, cable crossovers, various types of leg curls, and accessory hip work are well-tolerated by most folks, I chose the prone rear delt raise, hammer curl, and lateral raise in the scapular plane as the three best lifts for this category.

Since no overhead pressing will be performed, the shoulders will need some extra work to make up for the lack of compound shoulder exercises. And the hammer curl does a great job of strengthening the elbow flexors in a safe wrist position.

• With the prone rear delt raise, drape the head over the edge of the inclined bench so the neck isn't forced to hyperextend. Use the rear delts to transversely abduct the humeri, but also retract the scapulae using the mid traps and rhomboids so you get more bang for your buck.
• With the hammer curl, avoid using momentum and going too heavy.
• With the lateral raise in the scapular plane, make sure you stick to a 30-degree angle relative to the frontal plane (so it's 2/3^rd lateral raise and 1/3^rd front raise). Control the weight through the entire range of motion.

The three keys to injury prevention in the weight room are to avoid going too heavy, become obsessive about sound technical form, and avoid going to failure. But if progressive overload is continuously sought, problems will inevitably arise for certain lifters with crappy soft-tissue genetics, even if they obey all the rules.

I argue that these challenged lifters should stray from the big, heavy basics and stick to the 21 exercises included in this article. Doing so will allow them to train injury-free year in and year out while reaping much of the hypertrophy and strength benefits of a more "hard-core" exercise regimen.

A lifter who can bust out 275-pound single leg RDL's, 225-pound Bulgarian split squats, and 140-pound dumbbell bench presses for reps could probably deadlift 500, squat 400, and bench 300 if need-be. Yet he wouldn't be exposing his joints to the consistent pounding, thereby enabling him to make much more consistent gains in progressive overload and muscularity over time.

If you can squat, bench, deadlift, press, and chin week in and week out with no problems, then continue what you're doing. But if you're spinning your wheels in terms of progress and constantly training around injuries, then fess up – there's probably a better way for you to train.