Stephen P. Messier

Effects of intensive diet and exercise on knee joint loads, inflammation, and clinical outcomes among overweight and obese adults with knee osteoarthritis: the IDEA randomized clinical trial.

IMPORTANCE Knee osteoarthritis (OA), a common cause of chronic pain and disability, has biomechanical and inflammatory origins and is exacerbated by obesity. OBJECTIVE To determine whether a ≥10% reduction in body weight induced by diet, with or without exercise, would improve mechanistic and clinical outcomes more than exercise alone. DESIGN, SETTING, AND PARTICIPANTS Single-blind, 18-month, randomized clinical trial at Wake Forest University between July 2006 and April 2011. The diet and exercise interventions were center-based with options for the exercise groups to transition to a home-based program. Participants were 454 overweight and obese older community-dwelling adults (age ≥55 years with body mass index of 27-41) with pain and radiographic knee OA. INTERVENTIONS Intensive diet-induced weight loss plus exercise, intensive diet-induced weight loss, or exercise. MAIN OUTCOMES AND MEASURES Mechanistic primary outcomes: knee joint compressive force and plasma IL-6 levels; secondary clinical outcomes: self-reported pain (range, 0-20), function (range, 0-68), mobility, and health-related quality of life (range, 0-100). RESULTS Three hundred ninety-nine participants (88%) completed the study. Mean weight loss for diet + exercise participants was 10.6 kg (11.4%); for the diet group, 8.9 kg (9.5%); and for the exercise group, 1.8 kg (2.0%). After 18 months, knee compressive forces were lower in diet participants (mean, 2487 N; 95% CI, 2393 to 2581) compared with exercise participants (2687 N; 95% CI, 2590 to 2784, pairwise difference [Δ](exercise vs diet )= 200 N; 95% CI, 55 to 345; P = .007). Concentrations of IL-6 were lower in diet + exercise (2.7 pg/mL; 95% CI, 2.5 to 3.0) and diet participants (2.7 pg/mL; 95% CI, 2.4 to 3.0) compared with exercise participants (3.1 pg/mL; 95% CI, 2.9 to 3.4; Δ(exercise vs diet + exercise) = 0.39 pg/mL; 95% CI, -0.03 to 0.81; P = .007; Δ(exercise vs diet )= 0.43 pg/mL; 95% CI, 0.01 to 0.85, P = .006). The diet + exercise group had less pain (3.6; 95% CI, 3.2 to 4.1) and better function (14.1; 95% CI, 12.6 to 15.6) than both the diet group (4.8; 95% CI, 4.3 to 5.2) and exercise group (4.7; 95% CI, 4.2 to 5.1, Δ(exercise vs diet + exercise) = 1.02; 95% CI, 0.33 to 1.71; P(pain) = .004; 18.4; 95% CI, 16.9 to 19.9; Δ(exercise vs diet + exercise), 4.29; 95% CI, 2.07 to 6.50; P(function )< .001). The diet + exercise group (44.7; 95% CI, 43.4 to 46.0) also had better physical health-related quality of life scores than the exercise group (41.9; 95% CI, 40.5 to 43.2; Δ(exercise vs diet + exercise) = -2.81; 95% CI, -4.76 to -0.86; P = .005). CONCLUSIONS AND RELEVANCE Among overweight and obese adults with knee OA, after 18 months, participants in the diet + exercise and diet groups had more weight loss and greater reductions in IL-6 levels than those in the exercise group; those in the diet group had greater reductions in knee compressive force than those in the exercise group. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00381290.

Etiologic factors associated with selected running injuries

The purpose of this study was to determine whether a relationship exists between selected biomechanical, anthropometric, and training variables and runners afflicted with one of the following injuries: iliotibial (IT) band friction syndrome, shin splints, and plantar fasciitis. Competitive and recreational runners were divided into a non-injured control group (N = 19), an IT band friction syndrome injury group (N = 13), a shin splint injury group (N = 17), and a plantar fasciitis injury group (N = 15). Discriminant function analysis of the biomechanical data revealed two significant (P less than 0.05) discriminators between the control and shin splint groups; maximum pronation velocity and maximum pronation. Analysis of the anthropometric and training data revealed that plantar flexion range of motion was a significant (P less than 0.05) discriminator between the control and plantar fasciitis groups. In addition, analysis of the descriptive statistics (mean +/- SE) identified some non-significant (P greater than 0.05) trends between the injury and control groups: maximum pronation, total rearfoot movement, and maximum velocity of pronation were greater in the injury groups; the injury groups showed a trend toward a higher arch; dorsiflexion range of motion was less in the shin splint group; a greater percentage of injured runners had a leg length difference (greater than 0.64 cm); 20% more runners in the injury groups ran hills; and 20% more of the runners in the IT band friction syndrome group ran on crowned roads.

Exercise and weight loss in obese older adults with knee osteoarthritis: a preliminary study.

OBJECTIVE: The purposes of this pilot study were to determine if a combined dietary and exercise intervention would result in significant weight loss in older obese adults with knee osteoarthritis, and to compare the effects of exercise plus dietary therapy with exercise alone on gait, strength, knee pain, biomarkers of cartilage degradation, and physical function.

Etiologic factors associated with patellofemoral pain in runners

The purpose of this study was to extend our knowledge of running related injuries by determining whether relationships exist between selected anthropometric, biomechanical, muscular strength and endurance, and training variables and runners afflicted with patellofemoral pain (PFP). Specifically, the objectives of this study were to examine differences in selected measures between a non-injured control group (C) of runners (N = 20) and a group of injured runners (INJ) diagnosed by an orthopedic surgeon as having PFP (N = 16). High speed photography, a force platform, and isokinetic dynamometry were used to determine rearfoot motion, ground reaction forces, and knee muscular strength and endurance. Stepwise discriminant function analyses were performed on the anthropometric, biomechanical, and muscular strength and endurance variables. Q angle was a significant discriminator (P less than 0.01) between the INJ and C groups. The muscular endurance data revealed several significant discriminators with the INJ subjects being weaker in knee extension endurance. Kinetic analysis revealed several significant discriminators whereas rearfoot movement variables were not good discriminators between the groups. The training data revealed that the INJ group ran significantly less (P less than 0.01) miles.wk-1 than the C group. Our results suggest that Q angle is a strong discriminator between runners afflicted with PFP and non-injured runners. In addition, several muscular endurance and kinetic variables may also be important components of the etiology of PFP.

Long‐Term Exercise and its Effect on Balance in Older, Osteoarthritic Adults: Results from the Fitness, Arthritis, and Seniors Trial (FAST)

OBJECTIVES: To examine the effects of 18‐month aerobic walking and strength training programs on static postural stability among older adults with knee osteoarthritis.

Etiologic factors associated with anterior knee pain in distance runners.

PURPOSE The objectives of this study were 1) to examine the differences between a noninjured (C) cohort of runners (N = 70) and runners afflicted with anterior knee pain (AKP) according to selected training, anthropometric, rearfoot motion, ground reaction force, and muscular strength and endurance variables; 2) to explore multivariate relationships among these measures in the well and injured groups; and 3) to develop specific hypotheses concerning risk factors for injury that will later be tested in a prospective clinical study. METHODS High speed videography (200 frames x s(-1)), a force platform (500 Hz), and a Cybex II+ isokinetic dynamometer were used to assess rearfoot motion, ground reaction forces, and knee muscular strength and endurance, respectively. A linear discriminant function was performed on each of the five categories of variables and revealed 19 significant (P < or = 0.05) predictors. These variables were then combined and a final discriminant function analysis was performed. RESULTS Pronation through the first 10% of stance, arch index, shoe mileage, and extension peak torque were the best overall (P < or = 0.05) predictors. The AKP group had smaller mean values on all four significant predictors. CONCLUSION With the exception of shoe mileage, which is likely a response to rather than a risk factor for AKP, these results should prove useful to clinicians in identifying runners at risk for anterior knee pain.

Intensive Weight Loss Program Improves Physical Function in Older Obese Adults with Knee Osteoarthritis

Objective: Physical function and body composition in older obese adults with knee osteoarthritis (OA) were examined after intensive weight loss.

Osteoarthritis of the knee and associated factors of age and obesity: effects on gait.

1) A majority of people afflicted with osteoarthritis (OA) of the knee are elderly and many have their OA exacerbated by obesity. 2) Healthy older adults exhibit gait patterns that differ from a healthy, younger cohort. These differences include a slower walking velocity, slower cadence, shorter step length, reduced hip and knee range of motion, and greater stride width, vertical oscillation, and lateral sway of the head. 3) Subjects afflicted with knee OA have decreased knee range of motion and knee angular velocity, increased loading rate on the less affected leg, and a compensatory increase in hip angular velocity when compared with age matched healthy subjects. 4) Obesity, which is strongly associated with knee OA, increases rearfoot motion during walking and causes the forefoot to abduct significantly more than in normal weight individuals.

Etiologic factors associated with Achilles tendinitis in runners

PURPOSE The purpose of this study was to determine whether relationships exist between selected training, anthropometric, isokinetic muscular strength, and endurance, ground reaction force, and rearfoot movement variables in runners afflicted with Achilles tendinitis. METHODS Specifically, we examined differences in selected measures between a noninjured cohort of runners (N = 58) and a cohort of injured runners with Achilles tendinitis (N = 31). Isokinetic, kinetic, and kinematic measures were collected using a Cybex II+ isokinetic dynamometer (Medway, MA), AMTI force plate (500 Hz), and Motion Analysis high-speed videography (200 Hz), respectively. Separate discriminant function analyses were performed on each of the five sets of variables to identify the factors that best discriminate between the injured and control groups. RESULTS Years running, training pace, stretching habits (injured runners were less likely to incorporate stretching into their training routine), touchdown angle, plantar flexion peak torque at 180 degrees x s(-1) and arch index were found to be significant discriminators. CONCLUSION A combined discriminant analysis using the above mentioned significant variables revealed that plantar flexion peak torque, touchdown angle, and years running were the strongest discriminators between runners afflicted with Achilles tendinitis and runners who had no history of overuse injury.

Strength, balance, and the modifying effects of obesity and knee pain: Results from the observational arthritis study in seniors (OASIS)

OBJECTIVE: To examine the relationship between muscular strength and dynamic balance in a sample of older adults with knee pain and to determine the role that obesity and severity of knee pain play in the ability to maintain balance.