I must admit, that this site is one of the most complete one I've ever seen. But some of the exercises depicted have serious flaws to them. Take for example the stiff-legged deadlift. In the clip, the individual loses his lordosis during the lowering of the bar. This will only ensure ligaments being stretched and create greater instability in the lumbar region. Same applies for the Seated Row. Leaning over while returning puts the stress solely on the ligaments of the spine since the musculature is relaxed. Also, the incline sit-up can also create some pressure unto the lumbars from the PSoas muscle. Having your feet anchored actives the movement from the origin rather than the insertion. One last suggestion, would be the exercises for low back and recuperation. Most low back problem are caused from lack of flexibility/muscular lateral imbalance. Working the core stability and flexibility rather than weight training would be most beneficial for those people. I'm sure you can relate to these issues and hopefully make corrections. After all, its for everyone's good.
Concerned visitor (Bsc. Kin., PFLC)
The causes of lower back injury are poorly understood (Nelson 1993). Although the views you express are popular, I used to hold similar beliefs, other authorities and I disagree with this oversimplified theory. These generalizations are in contrast certain peer refereed journals, academic texts, empirical evidence, and my professional experiences.
Commonly held beliefs on the causes of injury are often not supported by scientific studies. For example, a past colleague performed an exhaustive review of the scientific literature on the problems associated with hyperextension of the lumbar spine during the bench press. This posture is performed by most powerlifters. He found no studies remotely demonstrating problems with this posture despite commonly held beliefs in the exercise community.
It is interesting that many orthopedic surgeons denounce certain commonly performed exercises. For example, some physicians condemn squats citing how destructive they are to the knees despite scientific studies and millions of personal experiences to the contrary. It is undeniable that people can hurt themselves on any exercise, more some than others, but the issue is much more complex than the exercise itself.
During the first portion of the sit up, the abdominal muscle flex the spine. The hip flexor muscles flex the hip to complete the movement. If the abdominal muscles are not strong enough to counter the Psoas' pull on the spine, the lumbar vertebrae can be forced into hyperextension. This can occur during other hip flexor movements as well.
In the book "Strength Training for Young Athletes" by Kraemer and Fleck, the cover states "Includes over 100 safe exercises for 18 muscle groups and 16 sports. They include two sit up exercises with the feet anchored
Steven J. Fleck, PhD and William J. Kraemer, PhD are probably the most well respected scientists studying resistive training. Fleck and Kreamer have dedicated their careers in investigating researching, and writing both scientific and main stream publications on weight training.
Kreighbaum (1996) states: "The physical condition of the performer dictates how safe and effective these exercises will be in the strengthening the abdominal"
For those with no history of lower back pain during hip flexion, situps or leg-hip raises can be concidered so the abdominal and hip flexors can be exercised in a single exercise. A determination should be made if the client has adequate abdominal strength to counter the psoas' pull. Like the lower back integrity previously discussed, this biomechanical deficiency can be easily corrected (see links immediately below). In some cases crunches, or half sit ups can be performed for the first months before the introduction of hip flexor movements.
Incidentally the bend of the hip severally diminishes Psoas' mechanical efficiency and consequently its pull on the lumbar spine. See tension potential. Kreighbaum (1996) adds: "For a performer with weak abdominal, the hip-flexed position is the best".
Flexible hip flexors and strong abdominal muscles are particular important before performing the Decline Situp, Roman Chair Situp, Leg Raises and Hip Raises since the hip becomes fully extended.
As for having your feet anchored effecting movement from the origin rather than the insertion, this essentially does not effect its activation. The muscle contracts through out itself despite the end that moves (origin or insertion). Are the forces through the Latissimus Dorsi some how different in pullup as compared to the pulldown? Your old physics or biomechanics book will clarify the forces are indistinguishable. Incidentally, the crest of the pubis is often referred to as the origin of the Rectus Abdominis, anyway. Obviously, man made classification systems do not perfectly fit all constructs; these semantics merely propitiate rhetorical arguments.
In a horizontal position, the anchoring of the feet will allow you to stabilize the lower body without extending the legs to counter the leverage and momentive forces of the upper body during its extended leverage in the lower position. Remember when the hips are extended the Psoas is activated more. In an incline motion, the anchoring of the feet prevents you from sliding back, or falling on your head.
If a client has such weak abdominal that their psoas is pulling on the back, corrective exercise should be performed months before they start on intense hip flexor exercises. To say sit ups are bad, or any other exercise is bad is a gross over-generalization.
The Cable Seated Row is an excellent movement to condition both the upper and lower back. Even Arnold Schwarzenegger as well as countless other weight trainers perform their cable rows with an articulating spine.
The body adapts to specific stresses placed on the body as long as certain principles are followed. Both the muscles and joint structures can adapt to progressive stresses. Even the elastic limit of a tendon or ligament can be enhanced by exercise and training and can be reduced by aging and inactivity (Tendon and ligament adaptation). Ligaments are not inert.
During the seated row with spinal articulation you say, "Leaning over while returning puts the stress solely on the ligaments of the spine since the musculature is relaxed." In order relax the muscles of the lower back, the exerciser would have to set down the resistance weight and pause. Even if the exerciser deliberately relaxed the musculature with the spine completely flexed, the stretch in the lower back muscles would activate the muscle spindles, or stretch receptors, maintaining an involuntary contraction for several seconds. As with any exercise, moving through the full range of a joint's motion is recommended, yet not beyond.
Ironically, splinting the lower back during all movements can lead to the degeneration of the joint structures of the spine (Nelson 1993, 1995). Including an exercise such as the cable seated row that involves actual (dynamic) movement joint structures and accompanying muscles are essential for lower back integrity and health. As the saying goes "If you do not use it, you lose it".
The Cable Straight Back Seated Row has been included for those who desire less lower back involvement during this movement.
Fleck and Falkel (1986) site a study that demonstrates compression forces are not excessive when the lumbar spine is flexed and the weight is held close to the body. In addition, intra-abdominal pressures generated during heavy lifts reduce extensor movements, thus further reducing stresses on the lumbar spine.
These techniques are used in the execution of the straight leg deadlift. Notice the weight is lowered to the top of the feet and not just beyond the feet. Illustrations in articles suggesting destructive forces on the spine are quite different than the straight leg deadlift. According to the ExRx description and animation the weight is kept very close to the body. Positioning the resistance away from the body subjects forces on spine structures much greater than the straight leg deadlift described.
I personally have not seen a higher incidence of injury to my clients on the straight leg deadlift as compared to other exercises. I certainly agree it would be a risk to perform the straight leg deadlift for individuals with certain low back disorders, or those who do not conform to the 4 adaptation criteria outlined on this site. Although many individuals from industrialized countries suffer from lower back pain, if I were to remove the straight leg deadlift and other exercises based upon certain people's idiosyncrasies, there would be few exercise to left to demonstrate.
For those who can not or do not care to perform this exercise with flexion in the spine see:
Lack of recuperation is only one of four reasons of injury as outlined in the ExRx site. Like you, I once believed lower back pain was mainly caused by a weak abdominal, flexibility, etc. until I meet a researcher whose team published their findings referenced below. The studies and accompanying papers strongly suggest other biomechanical factors contributed to the health of the lower back, specifically lower back strength throughout a complete range of motion. The artificial splinting of the lower back that so many professionals advocate is a short term solution. The avoidance of full range of motion promotes deconditioning and consequently deterioration of the joint structures. (Nelson 1993, 1995) This short sightedness is in total contradiction of the most basic principles of exercise: specific adaptation to imposed demands (SAID).
I have supervised hundreds of individuals who have performed the straight leg deadlift and similar exercises with excellent results. Individuals with ocassional lower back pain have reported dramatically less low back discomfort. One of my clients was 73 years old! For my clients with occasional lower back pain, I most often start them on the Lever Back Extension or Cable Seated Row with spinal articulation and perhaps later move them into Hyperextensions.
After a few months or so on these preliminary exercises, I introduce my clients to the straight leg deadlift with a 10-20 lb bar and progress them systematically (See Shorthand Log). When people stopped this exercise for a few weeks they report their old sporadic lower back pain comes back. This went away after resuming their program. I often find it difficult to persuade some clients to try other exercises after a month on the straight leg deadlift due to their excellent results.
I perform the straight leg deadlifts working up to 495 lbs with complete spinal flexion with the bar touching the top of my feet. I can personally assure you I have little instability in the lumbar region after years and years of regularly performing this exercise.
The straight leg deadlift with a rounded back is suggested by other experts including Greg Shepard, the Author of Bigger Faster Stronger, pg 90-91. His program has been used by more than 9000 high schools over the past 30 years.
In first edition of "Strength Training for Young Athletes" by Kraemer and Fleck, the cover states "Includes over 100 safe exercises for 18 muscle groups and 16 sports. They include two exercise similar to the straight leg deadlift:
In their book, the illustration of the Rounded-back Stiff-Legged Deadlift appears as though the boy was using 135 lbs. Dr. Fleck and Dr. Kraemer's credentials are impeccable.
Experts such as Fleck and Nelson, as well as the ACSM weight training guidelines all recommend implimenting full range of motion resistive exercises.
The limitations of an exercise program should be customized for each individual, not the general population as some exercise professionals have proposed. The individual's goals, medical history, orthopedic health, etc. as well as the limitations of the exercise professional's knowledge need to be considered. Obviously, certain exercises may be considered contraindicative for some people, at least until particular injuries and biomechanical deficiencies are corrected and the principles of specific adaptation can be observed.