Tuesday, September 22, 2015

5 Things You Should NEVER Do in the Gym (Backed by Science)

Certain exercises and training practices will break your body down over time, pretty much regardless of how well executed they are. Here’s a list of 5 Things You Should NEVER Do in the Gym, with references to the scientific literature to back each one up. Be sure to read to the bottom so you don’t miss anything.

Which of these 5 things do you do/recommend?

Deep squats
Low intensity cardio
Lift before puberty
Lift heavy weights when "toning" is the goal


1. Deep squats

Due to the excessive anterior translation of the knees past the toes and the resulting high compressive and shear forces at the knee joint, deep squatting greatly increases the risk of injury to the menisci and ACL (Escamilla 2001), as well as development of arthritis (Hefzy et al. 1998). In addition, squatting below parallel does not increase muscle activation (Escamilla 2001). Finally, the deep squat position is rarely required in the majority of sports, so its functional benefits are minimal (Schoenfeld and Williams 2012). For these reasons, deep squats should be avoided.

2. Deadlift

The deadlift exposes the spine to excessive loading. Due to the poor mechanical advantage of the exercise, the muscles of the low back must produce forces over ten times greater than the amount of weight being lifted (Harmon 2008). In powerlifters the compressive loads at the lumbar spine have been shown to exceed 3,000 pounds (Cholewicki et al. 1991)! Consequently, deadlifting can significantly increase the risk of bulging a disc (Gardner and Cole 1999) and should therefore be avoided.

3. Low intensity cardio when attempting to build muscle

Studies show that muscle and strength gains can be diminished by as much as 50% when cardio is programmed concurrently with resistance training (Kraemer et al. 1995; Dolezal and Potteiger 1998). Thus, due to the antagonistic effects of endurance training and strength training, it’s best to avoid training the cardiovascular system during phases in which muscle hypertrophy is the primary goal. If endurance is essential to sport, cardio should be performed at high intensity in order to avoid decrements in hypertrophy (Wilson et al. 2012).

4. Lifting weights before puberty

Growth cartilage, or “pre-bone,” can be found at three main sites in a growing child’s body: growth plates at the end of bones, articular cartilage, and tendon-bone attachments. Due to the relative weakness of growth cartilage compared to surrounding tissue, it is easily damaged (Micheli 2006). In fact, a number of case studies have shown that heavy weight training is injurious to this growth cartilage in children (Gums et al. 1982). Hence, resistance training should be avoided before maturity.

5. Lifting heavy weights if your goal is to tone

The use of weights that are high percentages of a woman’s one-repetition max have been shown to increase muscle cross-sectional area by as much as 45% (Staron et al. 1990)! To avoid gaining excessive muscle mass, err on the side of lighter weights and higher reps.

The Truth

Before reading this post, you may have been under the impression that all of the above gym exercises and practices were actually safe and effective.

You were right.

Allow me to break down the arguments point-by-point:

1. Deep squats

The Schoenfeld and Williams paper from 2012 is actually a point/counterpoint in which Schoenfeld takes the pro deep squat side and concludes that deep squats are, in fact, a safe and effective exercise for individuals with healthy knees.

2. Deadlift

It’s true that loading of the spine is high in heavy deadlifts, and this is certainly a risk that elite powerlifters assume. However, tissue adapts to the stresses imposed. Through use of proper form, sub-maximal loads, and progressive overload, the risk of injury is reduced. Opting for a kettlebell or hex bar over the traditional straight bar can further reduce spinal loading.

3. Low intensity cardio when attempting to build muscle

From a practical standpoint — provided you don’t do an excessive amount of it — low intensity cardio will not make you lose all your gains. But what constitutes excessive? A meta-analysis by Wilson et al. in 2012 found the threshold for “interference” to be >3 days and >20-30 minutes per bout. In addition, moderate amounts of cardio can actually enhance between-set and between-workout recovery, which will only augment one’s ability to build muscle.

4. Lifting weights before puberty

There’s actually no evidence suggesting resistance training stunts growth and maturation in preadolescents — and plenty of evidence that it doesn’t (Falk and Eliakim 2003; Malina 2006). Reports of growth plate fractures are most likely attributable to misuse of equipment, inappropriate loading parameters, and improper form (Caine et al. 2006; Gums et al. 1982).

Of course, training for 18 hours per day is unwarranted and will stunt growth (Theintz et al. 1993). But engaging in a sensible amount of sub-maximal resistance training and learning proper technique under the supervision of a qualified coach is perfectly safe and salubrious — even at an early age (Faigenbaum et al. 2009).

5. Lifting heavy weights if your goal is to tone

The vast majority of women who engage in resistance training will not blow up to the size of the woman pictured above. It takes a rare combination of genetics, drugs, and probably photoshop to look that big. In that 1990 study by Staron et al., although resistance training did result in increases in lean body mass and cross-sectional area of the quadriceps, there was actually no change in thigh girth due to an accompanying decrease in body fat (i.e. “toning!”).

In reality, women simply cannot become as muscular as men — even if they lift heavy. In a study of male and female bodybuilders, cross-sectional area of the biceps was 76% greater in the men than the woman (Alway et al. 1992). Moreover, the latest research is showing commensurate muscle hypertrophy with both high- and low-load training carried out to failure (Schoenfeld et al. 2015). So that whole light-weight-high-rep-for-toning thing? It’s pure myth. Women can and should lift heavy without the fear of getting bulky.

See What I Did There?

Perhaps you see what I did there. I “cherry picked” from the literature. That is, in the top section, I chose studies that directly supported the claims I was making.

For just about every scientific journal article that says one thing, you can find another that says the opposite. For this reason — although it can be exhausting — we must always consider the entire "body of evidence," not just a single study, when attempting to determine the safety and efficacy of a particular exercise or gym practice.

Read more about evidence-based training here: Evidence-based or Schmevidence-based.


Escamilla RF. Knee Biomechanics of the Dynamic Squat Exercise. Med Sci Sports Exerc 33(1): 127–141, 2001.
Hefzy MS, Kelly BP, and Cooke DV. Kinematics of the knee joint in deep flexion: A radiographic assessment. Med Eng Phys 20(4): 302–307, 1998.
Schoenfeld B and Williams M. Are Deep Squats a Safe and Viable Exercise? Strength Cond J 34(2): 34-36, 2012.
Harmon E. The Biomechanics of Resistance Exercise. In: Essentials of Strength and Conditioning (3rd ed.). Baechle TR and Earle RW, eds. Champaign, IL: Human Kinetics, 2008.
Cholewicki J, McGill SM, and Norman RW. Lumbar spine loads during the lifting of extremely heavy weights. Med Sci Sports Exerc 23(1):1179-1186, 1991.
Gardner PJ and Cole D. The Stiff-Legged Deadlift. Strength Cond J 21(5): 7-14, 1999.
Kraemer WJ, Patton JF, Gordon SE, Harman EA, Deschenes MR, Reynolds K, Newton RU, Triplett NT, and Dziados JE. Compatibility of high-intensity strength and endurance training on hormonal and skeletal muscle adaptations. J Appl Physiol 78(3): p. 976-89, 1995.
Dolezal BA and Potteiger JA. Concurrent resistance and endurance training influence basal metabolic rate in nondieting individuals. J Appl Physiol 85(2): 695-700, 1998.
Micheli, L. Preventing injuries in sports: What the team physician needs to know. In: F.I.M.S. Team Physician Manual (2nd ed.). Chan K, Micheli L, Smith A, Rolf C, Bachl N, Frontera W, and Alenabi T, eds. Hong Kong: CD Concept, 2006.
Gumbs V, Segal D, Halligan J, and Lower G. Bilateral distal radius and ulnar fractures in adolescent weight lifters. Am J Sports Med 10: 375–379, 1982.
Staron RS, Malickly ES, Leonardi MJ, Falkel JE, Hagerman FC, and Dudley GA. Muscle hypertrophy and fast fiber type conversions in heavy resistance-trained women. Eur J Appl Physiol Occup Physiol 60(1): 71-9, 1990.
Wilson JM, Marin PJ, Rhea MR, Wilson SM, Loenneke JP, and Anderson JC. Concurrent Training: A meta analysis examining interference of aerobic and resistance exercise. J Strength Cond Res 26(8): 2293-2307, 2012.
Falk B and Eliakim A. Resistance training, skeletal muscle and growth. Pediatr Endocrinol Rev 1: 120–127, 2003.
Malina R. Weight training in youth-growth, maturation and safety: An evidenced based review. Clin J Sports Med 16: 478–487, 2006.
Caine D, DiFiori J, Maffulli N. Physeal injuries in children’s and youth sports: reasons for concern? Br J Sports Med 40(9): 749-60, 2006.
Theintz GE, Howald H, Weiss U, and Sizonenko PC. Evidence for a reduction of growth potential in adolescent female gymnasts. J Pediatr 122(2), 306-313, 1993.
Faigenbaum AD, Kraemer WJ, Blimkie CJ, Jeffreys I, Micheli LJ, Nitka M, and Rowland TW. Youth resistance training: updated position statement paper from the national strength and conditioning association. J Strength Cond Res 23(5 Suppl): S60-79, 2009.
Always SE, Grumbt WH, Stray-Gunderson J, and Gonyea WJ. Effects of resistance training on elbow flexors of high competitive bodybuilders. J Appl Physiol 72(4): 1512-1521, 1992.
Schoenfeld BJ, Peterson MD, Ogborn D, Contreras B, and Sonmez GT. Effects of Low- Versus High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men. J Strength Cond Res, 2015. [Epub ahead of print] 

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