Research Review By Kevin Neeld©

Date Posted:

September 2009

Study Title:

Early-Phase Adaptations to a Split-Body, Linear Periodization Resistance Training Program in College-Aged and Middle-Aged Men


Kerksick CM et al.

Author's Affiliations:

Health and Exercise Science Department, University of Oklahoma; Department of Exercise and Sport Sciences, University of Mary Hardin-Baylor; School of Physical Education and Exercise Science, University of South Florida; Department of Health, Human Performance and Recreation, Baylor University; Department of Health and Kinesiology, Texas A&M University.

Publication Information:

Journal of Strength and Conditioning Research 2009; 23(3): 962-971.

Background Information:

Periodization, or the alteration of training variables such as volume, intensity, and rest, is universally accepted as a necessity in any effective training program. Of the periodization models, linear and undulating have gained the most attention. Linear periodization refers to gradually increasing the intensity and decreasing the volume across cycles of training (e.g. every 2-4 weeks). Undulating periodization involves changing volume and/or intensity on a daily or weekly basis.

Previous research has shown that undulating periodization models may result in greater increases in strength than constant load or linear periodized training programs. However, most training studies utilize a full body training program.

Furthermore, there is a lack of studies seeking to find optimal training methods for the elderly, who experience a loss of muscle mass and strength with increasing age. Because older adults lose muscle mass and strength due to neural, endocrine, and cellular changes, it may be reasonable to assume that young adults and older adults would not adapt to a training program to the same extent that young adults would, yet little data exists to confidently support this conclusion.

The purpose of the current investigation was to compare adaptations in strength and body composition in younger and older previously resistance-trained men following a linearly periodized 8-week split body training program.

Pertinent Results:

  • College-aged (CA) participants consumed significantly more carbohydrates than the middle-aged (MA) participants (p = 0.005). No differences were found between the groups in caloric, protein, or fat intake.
  • No differences were found in either group for total upper-body or lower-body training volume. There were also no differences found between groups in the number of training hours per week prior the beginning the study.
  • Body mass increased slightly in both groups over the 8 weeks (p = 0.06). Interestingly, CA participants increased their fat mass significantly compared to MA participants (p < 0.05).
  • Both groups significantly increased their bench press and leg press 1 repetition maximum (1RM; p < 0.001). However, no changes were noted in either group for Wingate peak or average power.

Clinical Application & Conclusions:

This study provides evidence that a split body training program effectively and similarly increases upper and lower body strength in young and middle-aged adults. That the training had no effect on anaerobic capacity is likely due to a lack of specificity of training (e.g. no bike work or high intensity conditioning). Interestingly, the middle-aged group gained more lean muscle mass than the young adults, and lost fat, whereas the young adults actually gained fat.

This is important as these findings provide further evidence that resistance training alone can combat some of the deleterious effects of aging, specifically a decrease in muscle mass and strength, and increases in body fat. It is unclear from this study whether similar results would be achieved through full body training sessions. However, split programs allow for greater recovery between training sessions for each muscle group, and therefore have the advantage of allowing people to train at a higher volume and/or intensity for those muscles groups.

A typical recommendation for a full body training program is to train three days per week. Using a split body training program allows people to train four days per week, which may be more effective at creating a more frequent metabolic disturbance. This may explain the difference in fat loss between the two groups.

There is still a stigma amongst older adults that resistance training is either not safe or not for them. Another important take home from this study is that resistance training using relatively heavy loads is both safe and effective for a middle-aged population.

Following appropriate precautions, there is little reason to believe that similar training methods would be unsafe for populations older than those included in this study. It is the job of training professionals to educate older adults on the benefits of resistance training programs and to follow individual ability-based progressions (e.g. start with wall push-ups if the client can’t do push-ups on the floor).

Combining education with appropriate progressions will allow adults of all ages to improve their health and functional performance and improve trust and confidence in training professionals.

Study Methods:

Twenty-four college-aged (Average Age: 19.8 years; Height: 179.2cm; Weight: 81.3kg) and twenty-five middle-aged (Average Age: 41.9 years; Height: 177.5cm; Weight: 88.8kg) with over one year of resistance training experience participated in the study. Participants were excluded if they had ever used steroids, regularly participated in endurance training for >20 mins/session, or took creatine, HMB, thermogenics, or other supplements during the 8-week period beginning the study.

Following a familiarization session, all participants were tested for body composition (using dual x-ray absorptiometry or DEXA), bench press and leg press 1RM strength, and they also completed a 4-day diet log (3 week days and 1 weekend day). Participants then followed a linearly periodized, split body eight-week training program involving four training sessions per week, two upper body and two lower body. All major exercises were performed for three sets of ten repetitions for the first four weeks, and three sets of eight repetitions for the next four weeks.

The only exception was abdominal crunches, which were performed for three sets of twenty-five for all eight weeks. Participants were instructed to take a one-minute break between sets and a two-minute break between exercises.

Upper body exercises included: Bench press, chest flies, lat pull, seated row, shoulder press, shoulder shrugs, biceps curls, triceps extension. Lower body exercises included: Leg press, leg extensions, deadlift, lunges, lying leg curls, heel raises, and abdominal crunches.

Study Strengths / Weaknesses:

The study had a few notable limitations:
  • The two major limitations of this study were that it did not include female participants and that the older group was 35-50 years old. As a result, the findings of this investigation cannot be applied to females or adults older than 50. However, it is reasonable to presume that similar results would be found in these populations. Furthermore, the training sessions included many single-joint exercises that are becoming less common in new strength and conditioning programs. It seems to be the case that most trainers are also pairing exercises to maximize recovery between sets of the same exercise, while making the most out of the rest intervals. It would be interesting to see if the groups in the current study would have responded more favorably to a more current exercise selection, paired-exercise training session design, or an undulating periodization model.

Additional References:

  1. Hakkinen K et al. Changes in electromyographic activity, muscle fibre and force production characteristics during heavy resistance/power strength training in middle-aged and older men and women. Acta Physiol Scand 2001; 171: 51-62.
  2. Kraemer WJ et al. Changes in muscle hypertrophy in women with periodized resistance training. Med Sci Sports Exerc 2004; 36: 697-708.
  3. Moir G et al. The effect of periodized resistance training on accelerative sprint performance. Sports Biomech 2007; 6: 285-300.
  4. Newton RU et al. Mixed-methods resistance training increases power and strength of young and older men. J Strength Cond Res 2002; 34: 1367-1375.