Research Review By Demetry Assimakopoulos ©

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Date Posted:

August 2011

Study Title:

The response of persons with chronic nonspecific low back pain to three different volumes of periodized musculoskeletal rehabilitation

Authors:

Kell RT, Risi AD & Barden JM

Author's Affiliations:

School of Kinesiology, University of Regina; Department of Social Sciences, University of Alberta, Canada

Publication Information:

Journal of Strength and Conditioning Research 2011; 25(4): 1052-1064.

Background Information:

One of the most frequent diagnoses in health care is chronic nonspecific low back pain (CLBP) (2). A substantial amount of literature exists, proving that non-periodized weight lifting may reduce the symptoms of CLBP (1, 3) by increasing whole body strength and endurance (EDITOR’S NOTE: this may actually be what this study showed as well – see comments regarding the use of the term ‘periodization’ below).

As a result, one’s activities of daily living become easier, fatigue is reduced and the potential for injury and pain decrease. Because of the aforementioned research, the researchers who conducted this study assumed that a periodized musculoskeletal rehabilitation (PMR) model would also be beneficial.

Manipulating training volume and intensity are incredibly important when designing an effective resistance training program (4). However, no literature to date has incorporated periodized training into a rehabilitation program. Thus, the current research question is to discover which training volume yields the best results in a rehabilitation program for those suffering from CLBP. In an attempt to understand this relationship the researchers examined the influence of 3 different PMR training volumes on a group of middle-aged, untrained males and females suffering from CLBP.

Specifically, they sought to determine which periodized training volume is most effective at improving a patient’s strength and quality of life through reducing disability and pain over the course of 16 weeks. The training volumes included in this study were:
  1. 1563 reps/week over 4 days (4D)
  2. 1344 reps/week over 3 days (3D)
  3. 564 reps/week over 2 days (2D)
The researchers also wanted to determine if significant relationships exist between changes in strength and disability, pain and quality of life. They hypothesized that periodization training would yield significant (p ? 0.05) improvements in disability, strength and pain with the 3D and 4D training volumes being most affective. In addition, the researchers theorized that significant associations would exist between an increase in strength and pain, disability and quality of life.

Pertinent Results:

Physical Characteristics:
From baseline to week 13, the 3D and 4D training volumes yielded a significant (p ? 0.05) increase in lean body mass and a reduction in body fat. The 2D training volume did not accrue similar results. There were no significant differences between training volumes on body mass or percent body fat.

Musculoskeletal Strength:
All groups, with the exception of the control group, showed significant increases in strength (measured via the bench press, lat pull down and leg press) from baseline to weeks 9 and subsequently to week 13. The 3D and 4D groups showed significant strength increases in all strength tests. However, the 2D training group only realized significant strength gains in bench press and lat pull down but not leg press.

While at baseline there were no significant differences between groups in any measurement parameters, at weeks 9 and 13 the 4D group was significantly stronger than all groups. The control group was significantly weaker than both the 2D and the 3D groups in all strength tests at the same assessment periods. Additionally, the 3D group was significantly stronger than the 2D group in the lat pull and leg press tests. Put simply, the 4D group was strongest, followed by 3D, 2D and finally the control.

Relationships between Outcome Measures:
All groups, save the control group, yielded significant positive improvements in strength, pain, disability and quality of life between baseline and week 13. Because of this fairly uniform result between groups, the 4D, 3D and 2D periodized training volumes were combined to determine the relationships between variables. When this was done, a positive correlation (r = 0.82) was found between pain and disability. This strongly suggests that when pain decreases, disability decreases at the same time.

Pain, Disability and QOL:
Again, with the exception of the control group, all experimental groups demonstrated significant improvements in pain, disability and quality of life from baseline to week 9 and from baseline to week 13. The 4D, 3D and 2D groups also showed significant improvements in quality of life from weeks 9 – 13. However, groups 2D and 3D did not show significant improvements in pain and disability between weeks 9 – 13, whereas group 4D did. Suffice it to say, the 4D training group showed the greatest improvements in pain, disability and QoL throughout the training period, while groups 3D and 2D leveled off in these parameters after week 9.

Clinical Application & Conclusions:

The authors concluded that group 4D showed significantly less (p ? 0.05) pain and disability and had the most improvement in quality of life when compared to the other groups throughout the study. Between weeks 9 and 13 the 3D and 2D groups showed significant quality of life improvements with a decrease in pain and disability when compared to the control group. However, no significant difference was found between groups 3D and 2D on any of the measured variables at weeks 9 and 13.

Very generally, unsupervised periodized resistance training can be effective in rehabilitating chronic nonspecific low back pain. Additionally, the volume prescribed is important in the treatment outcome with a 4D periodization rehabilitation program being the most effective volume in the treatment of CLBP in this study.

Overall however, periodization programming improves strength and quality of life while decreasing disability. There were no negative effects or injuries reported by the subjects. Subsequent to the diagnosis of CLBP, those responsible for prescribing rehabilitative exercises to these patients should not hesitate to employ a gradual increase in training volume, eventually reaching volumes similar to those used by healthy individuals. By increasing a patient’s strength via weight training, the patient should experience a decrease in pain, disability and fatigue, while realizing an improved quality of life.

EDITOR’S NOTE: I thought this weakness of the study was important to emphasize so I’ve copied it from below:

"No specific operational definition was used for the term ‘periodization’ other than to explain that the manipulation of volume and intensity are important in creating effective resistance training programs. However, there was no apparent manipulation of training volume and intensity, as the researchers explained that the repetitions stayed at a value of 12, while the weight (or intensity/ 1RM), increased allowing for progressive increase in resistance to create overload at 12 repetitions. Aside from increasing the weight, the number of repetitions (or training volume) stayed the same for each group. In addition, no macro- or microcycle phases were included to achieve specific goals.

Without a specific definition of periodization, it is difficult to understand what the researchers were trying to prove regarding periodization as a concept, other than to say that active care is important in treating chronic pain, and that a 3 or 4 day/week program seems to offer the most benefits."

Typically, periodization refers to altering the training method and programming to reflect a different aspect of physical performance such as speed, agility, strength and so on. The authors’ slightly inappropriate use of this term does not, in my opinion, alter the take home message from this study, I just thought I would mention it since many of you were likely wondering.

Study Methods:

Experimental Approach:
To determine the influence of training volume on strength, pain and disability, three different training volumes (measured in reps/week) were used. In order to determine the specific relationship between these variables alone, training intensity, the type of exercises included in the routine, exercise order and rest time were held constant across all 3 groups, thus attributing all changes in strength, quality of life and disability to volume.

Subjects:
240 subjects were recruited for the duration of this study. The authors included male and female subjects between the ages of 18-50 diagnosed with chronic nonspecific low back pain by their physician (this diagnosis is defined as pain in the lumbar region, greater than or equal to 3 months in duration, greater than or equal to 3 days/week that is soft tissue in origin with a pain visual analog scale that is greater than or equal to 3/10). In this population, the duration of back pain ranged from 14-109 months.

Subjects were not included if they suffered from pain below the knee, spinal stenosis, herniated lumbar intervertebral discs, spondylolesthesis, spinal infection, scoliosis, rheumatological conditions, osteoporosis, a history of previous back surgery and if they consumed any prescription or over the counter medications. In addition, patients who had been previously diagnosed with metabolic, endocrine, neurological or cardiovascular disease were excluded as well.

The Godin Leisure-Time Exercise Questionnaire (GLTEQ) was used to identify the subjects’ level of activity. This determined that the subjects were either sedentary or performed low level, non-habitual physical activity and were thus untrained. The experimental groups also had no experience with resistance training in the past. The control group were able to seek any medical, physiotherapy or chiropractic treatment during the study but were prohibited from beginning any weight training exercise regimens.

When the study was complete, the control group was provided with a 12 week strength training program of their choice: either 2-days/week (2D), 3-days/week (3D or 4-days/week (4D). Over the course of the 12 week training program 33 subjects were lost to attrition; their data were not included in the statistical analysis.

Data Collection:
The study took place over the course of 16 weeks, with the first 3 weeks dedicated to assessment and familiarizing the subjects to the training regimen. The latter 13 weeks focused on periodized weight training with reassessments performed at week 4 (training week 1), week 8 (training week 5), week 12 (training week 9) and finally at week 16 (training week 13). Outcome questionnaires were completed at baseline and during reassessments at weeks 8 and 12.

The outcome measures considered for this study were changes in strength (bench press, lat pull down and leg press), body weight in kilograms, percent body fat, pain, disability and quality of life (please see the outcome measures section for more information).

Familiarization Phase:
The first 3 weeks of the study were used to acquaint the subjects with the repetition maximum (RM) protocol, neuromuscular control, exercise order and with the general surroundings of their fitness facility. Each subject performed a 5 RM max test on each exercise (leg press, leg extension, leg curl, bench press with free weights, incline bench press with free weights, lat pull down, low cable row, dumbbell shoulder press, dumbbell biceps curl and triceps pushdown) for a total of 10 exercises.

The first testing session established the load in kilograms for the 2 weeks of familiarization training. Subsequent familiarization training days consisted of 2-3 sets of all exercises listed above with the addition of abdominal crunches, Swiss ball crunches and prone superman exercises at 55-60% of 1RM, 10-12 repetitions/set with a 1-minute rest between sets. While performing the abdominal and Swiss ball crunches the subjects initially utilized only their body weight as resistance, but once they could complete 30 consecutive repetitions a free weight was added to their chest for additional resistance. The prone superman was only performed with body weight resistance at 10 reps/set with an isometric contraction held from 5-30 seconds/repetition.

Periodization Protocol:
Following baseline testing, the subjects were age, sex, strength (according to their scores in the bench press and leg press) and pain matched and randomly assigned to one of the 4 groups: 2D, 3D, 4D or control. Those assigned to the control group terminated all resistance training after the familiarization period.

For the 2D, 3D and 4D groups, a traditional periodized training program used. The only variation between groups was the number of repetitions performed per week. In this case, intensity was defined as the amount lifted or RM used to perform 12 reps in a set. While the 2D and 3D groups performed all 10 exercises on the same day, the 4D group performed a split routine that trained chest, back and core 2 days of the week and legs, shoulders and core on another 2 days.

As a result of this difference in scheduling, the exercise order could not be identical between all groups. However, the exercises were performed in the same order within each muscle region.

Outcome Measures:
Anthropometric and body composition measures taken during the fitness assessments were height (m), body mass (kg), lean body mass (kg) and percent body fat. Body mass, lean body mass and percent body fat were measured using a bioelectric impedance analysis to the nearest 0.1kg and 0.1% body fat.

Five RM testing was performed on all subjects, from which 1 RM values were extrapolated and predicted. Three tests were used to monitor strength: bench press using an Olympic level barbell touching the chest, leg press and wide grip seated lat pull down on a machine.

The Visual Analog Scale (VAS), Oswestry Disability Index (ODI) and the Short Form-36 (SF-36) were used to assess pain, disability and quality of life, respectfully. All 3 were completed at baseline, and at weeks 9 and 12.

Study Strengths / Weaknesses:

Strengths:
  1. The findings suggest that rehabilitation specialists that they can be aggressive in the treatment of chronic low back pain, as long as they stay within the confines of the patient’s overall functional/physical capacity.
  2. Many of the strategies used for the improvement of performance in athletes can be employed in a rehabilitation setting for injured persons, as long as the rehabilitation specialists regress the exercises to the level and capacity of the patient.
  3. This study exemplifies the importance of active care in the treatment of chronic pain.
Weaknesses:
  1. No specific operational definition was used for the term ‘periodization’ other than to explain that the manipulation of volume and intensity are important in creating effective resistance training programs. However, there was no apparent manipulation of training volume and intensity, as the researchers explained that the repetitions stayed at a value of 12, while the weight (or intensity/ 1RM), increased allowing for progressive increase in resistance to create overload at 12 repetitions. Aside from increasing the weight, the number of repetitions (or training volume) stayed the same for each group. In addition, no macro- or microcycle phases were included to achieve specific goals. Without a specific definition of periodization, it is difficult to understand what the researchers were trying to prove, other than to say that active care is important in treating chronic pain, and that a 3 or 4 day/week program seems to offer the most benefits.

Additional References:

  1. Bendix, T, Bendix, A, Labriola, M, Haestrup, C, and Ebbehoj, N. Functional restoration versus outpatient physical training in chronic low back pain: A randomized comparative study. Spine 25: 2494–2500, 2000.
  2. Deyo, RA and Weinstein, JN. Low back pain. N Engl J Med 344: 363–370, 2001
  3. Frost, H, Klaber Moffett, JA, Moser, JS, and Fairbank, JC. Randomised controlled trial for evaluation of fitness programme for patients with chronic low back pain. BMJ 310: 151–154, 1995
  4. Kraemer, WJ, Adams, K, Cafarelli, E, Dudley, GA, Dooly, C, Feigenbaum, MS, Fleck, SJ, Franklin, B, Fry, AC, Hoffman, JR, Newton, RU, Potteiger, J, Stone, MH, Ratamess, NA, and Triplett- McBride, T. American College of Sports Medicine position stand.Progression models in resistance training for healthy adults. Med Sci Sports Exerc 34: 364–380, 2002.