Robert T. Kell

Musculoskeletal Fitness, Health Outcomes and Quality of Life

AbstractThe health benefits and quality-of-life outcomes of a fit musculoskeletal system (musculoskeletal fitness) are reviewed in this article. The World Health Organization suggests health is a state of complete physical, mental or social well-being and not merely the absence of disease or infirmity. Physical health includes such characteristics as body size and shape, sensory acuity, susceptibility to disease and disorders, body functioning, recuperative ability and the ability to perform certain tasks.One aspect of physical health is the musculoskeletal system, which consists of 3 components; muscular strength, endurance and flexibility. Muscular strength (dynamic) is defined as the maximum force a muscle or muscle group can generate at a specific velocity. Muscular endurance is the ability of a muscle or muscle group to perform repeated contractions against a load for an extended period of time. Flexibility has 2 components, dynamic or static, where dynamic flexibility is the opposition or resistance of a joint to motion, that is, the forces opposing movement rather than the range of movement itself. Static flexibility is the range of motion about a joint, typically measured as the degree of arc at the end of joint movement. If strength, endurance and flexibility are not maintained, musculoskeletal fitness is then compromised which can significantly impact physical health and well-being.Many health benefits are associated with musculoskeletal fitness, such as reduced coronary risk factors, increased bone mineral density (reduced risk of osteoporosis), increased flexibility, improved glucose tolerance, and greater success in completion of activities of daily living (ADL).With aging, the performance of daily tasks can become a challenge. Additionally, falls, bone fractures and the need for institutional care indicate a musculoskeletal weakness as we age. The earlier in life an individual becomes physically active the greater the increase in positive health benefits; however, becoming physically active at any age will benefit overall health.Improved musculoskeletal fitness (for example, through resistance training combined with stretching) is associated with an enhanced health status. Thus, maintaining musculoskeletal fitness can increase overall quality of life.

A comparison of two forms of periodized exercise rehabilitation programs in the management of chronic nonspecific low-back pain.

Kell, RT, and Asmundson, GJG. A comparison of two forms of periodized exercise rehabilitation programs in the management of chronic nonspecific low-back pain. J Strength Cond Res 23(2): 513-523, 2009-The purpose of this study was to determine the influence of 2 different periodized exercise rehabilitation programs (resistance training [RT] and aerobic training [AT]) on musculoskeletal health, body composition, pain, disability, and quality of life (QOL) in chronic (≥3 months; ≥3 d·wk−1) nonspecific low-back pain (CLBP) persons. Twenty-seven CLBP subjects were randomly assigned to 1 of 3 groups, 1) RT (n = 9), 2) AT (n = 9), or 3) control (C; n = 9). Subjects were tested at baseline and at weeks 8 and 16 of training. Intensity and volume were periodized in the training groups. Significance was set at p ≤ 0.05. No significant differences were noted among the groups at baseline. The RT group significantly decreased body fat percent from baseline to week 8 and from baseline to week 16, whereas the AT group significantly decreased body fat percent and body mass from baseline to week 16. The RT group significantly improved most musculoskeletal fitness, pain, disability, and QOL outcomes from baseline to week 8, baseline to week 16, and weeks 8 to 16. However, the AT group showed significant improvements in flexibility from baseline to week 8 and in cardiorespiratory and peak leg power from baseline to week 8 and baseline to week 16. The AT groups showed no significant improvements in pain, disability, or QOL. The primary finding was that periodized RT was successful at improving many fitness, pain, disability, and QOL outcome measures, whereas AT was not. This study indicates that whole-body periodized RT can be used by training and conditioning personnel in the rehabilitation of those clients suffering with CLBP.

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

Kell, RT, Risi, AD, and Barden, JM. The response of persons with chronic nonspecific low back pain to three different volumes of periodized musculoskeletal rehabilitation. J Strength Cond Res 25(4): 1052-1064, 2011-Chronic nonspecific low back pain (CLBP) is a common musculoskeletal health issue associated with pain and disability reduced quality of life (QoL). Pain initiates a fear-avoidance cycle, which needs to be broken if rehabilitation is to work. To break this cycle, exercise must be gradual and focused on strengthening the weakened musculature. Recently, periodized resistance training was effectively used as a musculoskeletal rehabilitation for adults with CLBP. The purpose of this study was to determine if the volume of periodized musculoskeletal rehabilitation (PMR) influences strength, pain, disability, and QoL in untrained persons. Subjects (n = 240) were age and sex matched, with attempts made to match on strength and pain, and randomly assigned to groups after baseline testing: (a) 4 days per week (4D; n = 60), (b) 3 days per week (3D; n = 60) (c), 2 days per week (2D; n = 60) training volume or control (C; n = 60) with no training. The PMR program progressively overloaded muscle groups, with mean training volumes of 4D (1,563 repetitions [reps] per week), 3D (1,344 reps per week), and 2D (564 reps per week). Three weeks of familiarization and 13 weeks of PMR were employed. The 4D training volume significantly (p ≤ 0.05) outperformed all other training volumes by weeks 9 and 13. However, all training volumes made significant (p ≤ 0.05) improvements in strength, pain, disability, and QoL across time. The effect sizes (ESs) associated with the group means of the outcome measures ranged from moderate to strong, with the 4D training volume consistently demonstrating the largest ESs. The 4D training volume is most effective at treating CLBP. Periodization cannot only be applied to athlete training but also to the rehabilitation setting.

The influence of periodized resistance training on recreationally active males with chronic nonspecific low back pain.

Jackson, JK, Shepherd, TR, and Kell, RT. The influence of periodized resistance training on recreationally active males with chronic nonspecific low back pain. J Strength Cond Res 25(1): 242-251, 2011-The most common musculoskeletal health issue is chronic nonspecific low back pain (CLBP). CLBP increases pain and disability, which reduces quality of life (QoL). Generally, pain, disability, and QoL are improved with a moderate volume and intensity of physical activity. Recently, periodized resistance training (PRT) was shown to be effective at improving CLBP in sedentary young, middle-age, and older adults. The purpose of this study was to determine if PRT would increase strength, reduce pain and disability, and improve QoL in recreationally active, moderately trained middle- and older-age males. Forty-five male subjects were divided according to age into 1 of 3 groups: (a) middle-age exercise (ME), (b) old-age exercise (OE), or (c) control (C). All subjects suffered from CLBP and were considered to be moderately trained, participating in recreational ice hockey for 60 minutes, 2 times per wk−1 for ∼5 months/year along with other recreational activities. The study ran for 16 weeks (3-week familiarization and 13 weeks of testing and PRT) with 5 repetition maximum testing at baseline and weeks 8 and 12. The PRT program systematically and progressively overloaded all major muscle groups (whole-body workout). The results indicate that middle- and old-age recreationally active males with CLBP respond similarly in magnitude to PRT, with improvements in all outcome measures (strength, pain, disability, QoL) across all time points of the study. Clinical significance (≥25%) in outcome measures was reached on most variables for the ME and OE groups. The results suggest that PRT may be effectively applied as rehabilitation for moderately trained recreational athletes with CLBP.

A comparison of traditional and weekly undulating periodized strength training programs with total volume and intensity equated.

Apel, JM, Lacy, RM, and Kell, RT. A comparison of traditional and weekly undulating periodized strength training programs with total volume and intensity equated. J Strength Cond Res 25(3): 694-703, 2011-The purpose of this study was to compare the training adaptations attained during 12 weeks of traditional (TD) and weekly undulating (WUD) periodized strength training. Forty-two recreationally active men (age = 22 ± 2.3 years) were randomly assigned to 1 of 3 groups: control (C) (n = 14), TD (n = 14), or WUD (n = 14). Ten-repetition maximum (10RM) laboratory testing was carried out for the free weight back squat and the free weight flat bench press at baseline, week 8, and week 12. The subjects trained 3 d·wk−1 (approximately 135 min·wk−1) from weeks 1 to 2 and 4 d·wk−1 from week 3 to week 12 (approximately 180 min·wk−1). The TD and WUD groups trained using a periodized strength program with all program variables controlled (e.g., volume and intensity). The independent variable was the manipulation of intensity. The TD group used a linear increase in intensity, whereas the WUD group had a varied intensity. The results showed that both the TD and WUD groups made significant (p ≤ 0.05) increases in strength at weeks 8 and 12, but by week 12, the TD group was significantly (p ≤ 0.05) stronger than the WUD group. These results indicate that TD periodization with a linear increase in intensity was more effective at eliciting strength gains than WUD periodization with a varied intensity. The differences in strength gains between the TD and WUD groups may be related to extended periods of muscle soreness and fatigue that were present in the WUD group but not in the TD group. Thus, during long-term training, individuals may benefit more from TD periodized programs because there may be less muscle soreness and fatigue to disrupt practice and training.

In vivo erector spinae muscle blood volume and oxygenation measures during repetitive incremental lifting and lowering in chronic low back pain participants

Study Design. A case control study. Objectives. Using metabolic gas analysis and near infrared spectroscopy, a comparison was made between healthy controls and chronic low back pain (LBP) participants on cardiorespiratory, erector spinae muscle blood volume, and oxygenation responses, and these variables were used to determine factors that best predict peak oxygen consumption (VO2peak). Summary of Background Data. To date, it is unknown how the cardiorespiratory and erector spinae muscles of chronic LBP persons respond to repetitive incremental lifting and lowering. With the advent of near infrared spectroscopy technology, it is now possible to noninvasively examine erector spinae muscle oxygen supply and utilization in vivo. Thus, by using metabolic gas analysis and near infrared spectroscopy technology simultaneously, it is now possible to compare the cardiorespiratory and erector spinae muscle responses of chronic LBP participants to that of healthy controls (no history of LBP) during incremental work to volitional fatigue. Methods. Thirty-four participants with chronic LBP and 34 healthy controls completed the repetitive incremental lifting and lowering (2.25 kg · min−1) protocol from floor to table (height 76 cm) at 10 lifts · min−1 to voluntary fatigue. Results. The healthy controls had significantly greater VO2peak (mL · kg−1 · min−1) and VO2peak (mL · kgLBM−1 · min−1), peak mass lifted, test duration, and breathing frequency. Furthermore, healthy controls showed significantly greater change in muscle oxygenation and faster one-half recovery times. Multiple regression analysis indicated that approximately 97% of the variance in absolute VO2peak was predicted by cardiorespiratory variables in both groups, while muscle oxygenation aided in predicting VO2peak relative in the LBP participants. Conclusions. The results indicated that the chronic LBP participants demonstrated a reduced cardiorespiratory and erector spinae muscle response during repetitive incremental lifting and lowering to volitional fatigue as compared to the healthy controls.

The influence of periodized resistance training on strength changes in men and women.

Kell, RT. The influence of periodized resistance training on strength changes in men and women. J Strength Cond Res 25(3): 735-744, 2011-The purpose of this study was to contrast the response of previously resistance-trained male and female recreational athletes with a traditionally periodized resistance training program. Sixty subjects (age = 22.8 ± 4.5 years) were assigned to 3 groups: male training (MT), n = 20; female training (FT), n = 20; and control, n = 20 (men, n = 10; women, n = 10). The MT and FT groups completed 12 weeks of traditional periodized strength training, with strength testing at baseline and at weeks 8 and 12. The training programs were identical (e.g., rest time, exercises, volume, and intensity) in both groups. In weeks 1 and 2, the FT and MT groups were trained 3 d·wk−1 (324 repetitions [reps]·wk−1) and thereafter 4 d·wk−1 (mean 642 reps·wk−1). The mean volume and intensity over the 12 weeks was 571 reps·wk−1 and 69.7% of 1 repetition maximum. Results indicated that the men were significantly (p ≤ 0.05) stronger in absolute terms at baseline and at weeks 8 and 12. The FT group (increase = 26.2% at week 8 and 38.1% at week 12) made significantly (p ≤ 0.05) greater percent increases in strength than the MT group (increase = 17.7% at week 8 and 28.0% at week 12). The FT and MT groups made significant (p ≤ 0.05) changes in relative strength at all time points, but the MT group demonstrated greater relative strength on lateral pull-down and dumbbell shoulder press. In practical terms, the men were absolutely stronger than the women, but the women were more responsive to the periodized resistance training program. Twelve weeks of traditionally periodized resistance training induced meaningful strength gains in women (≥ 30%) and men (≥ 25%) with prior (approximately 11 months) nonperiodized resistance training experience.

The effect of critical speed and exercise intensity on stroke phase duration and bilateral asymmetry in 200-m front crawl swimming

Abstract The main aim of this study was to determine the absolute temporal relationship between the power and recovery phases of the stroke cycle in front crawl swimming in response to progressive changes in exercise intensity that occurred before and after critical speed. A second objective was to determine whether intensity-related changes in the power/recovery phase relationship affects the bilateral symmetry of the stroke. Stroke parameters were recorded for each 25-m length during a progressive 200-m interval training set, in which eight (2 males, 6 females) national-level swimmers swam at intensities below, above, and at critical speed. The results demonstrated that substantial increases in stroke rate (P < 0.01) occurred at critical speed, and that these increases were related to a greater decrease in the duration of the power phase than the recovery phase (P < 0.01). The results also show that the degree of bilateral asymmetry was greater for the power phase than the recovery phase, and was inversely related to intensity in both phases of the stroke cycle. The findings of this study suggest that critical speed-related increases in stroke rate are an indirect consequence of increased force production in the power phase of the stroke, and that bilateral asymmetry is both intensity- and stroke-phase dependent.