Train High Eat Low for Osteoarthritis: THE LO Study

We have designed a novel, evidence-based lifestyle modification program which targets most of the treatable aetiological factors in OA: “Train High Eat Low for Osteoarthritis” or THE LO Study). It i s important to study these components in additive fashion, however, a s there are no previous randomised controlled trial (RCT) data on the application of gait training or a low GI/GL diet alone in individuals with knee OA to our knowledge. As we have recently reviewed, there are a large number of randomised controlled trials (RCTs) of isolated resistance training for knee OA, including our own recent trial, and therefore less rationale for studying isolated PRT once again. Theoretically, each intervention will reduce KAM via a different pathway, and thus we anticipate a dose-response effect with the application of a singular component or all three components of the program. ARM 1 – GAIT RE-TRAINING (GAIT GROUP) Pelvic obliquity, trunk lean and insufficient leg flexion have been related to an increase in KAM, while increased medial-lateral sway, widened stance, knee flexion and altered toe position can lower KAM. Recognising that a single gait modification might not suit all participants, however, our strategy will beto ask subjects to adjust their gait in whatever way reduces pain and KAM, while receiving visual feedback reinforcement. The potential effectiveness of this motor learning approach for our proposed gait training intervention is supported by Wishart and Lee, who found that older adults in particular benefit from concurrent augmented visual feedback when learning a bimanual task. Similarly, we have shown that concurrent augmented visual feedback significantly improved patterns of work during an exercise task, compared with no augmented feedback. Ten trials of participants’ habitual gait will be recorded per 60-90 minute training session. During each of the habitual gait trials, the subject will be provided with visual and verbal feedback of their ground reaction force vector and the significance of the feedback will be explained. The participant will be shown how to alter his/her gait so as to reduce KAM and knee pain, and further gait trials will be recorded while the participant attempts to replicate this modified gait. Participant will be asked to rate the knee pain experienced during the each trial on a Likert pain scale and to report if using the modified gait introduces any other discomfort. Adequate rest will be provided after each trial. Participants will be asked to practice the new technique at home using a mirror each day for 10 minutes and to try to use the modified gait whenever walking. Home practice of the gait modification will be monitored and supported via a simple logbook, reviewed by educators weekly. Participants will return to the biomechanics laboratory to gain further feedback about their progress in mastering the pain-reducing gait technique once each week for one month. Over the month the number of trials during which feedback will be provided will be reduced until there is no feedback. Participants will be asked to return to the laboratory once per month for the duration of the 12-mo study for reinforcement and visual feedback of their modified gait. For each participant, the time series of the net joint forces, moments and powers will be evaluated for all ten trials using Cortex (ver. 2, Motion Analysis Corporation, USA). The research team will discuss the outcomes of this analysis together with the pain scale, post-data collection participant discussion results with the objective of optimising the magnitude of pain and KAM reduction at the participant’s next visit. ARM 2 – HIGH PROTEIN/LOW GLYCAEMIC LOAD DIET (DIET GROUP) Participants in this group will be coached to adopt a high protein/low GI weight loss diet. The goal of the diet is to reduce weight by 5-10% over 12 months with a sustainable change in eating patterns and moderate energy restriction similar to the diabetes prevention programs. The target macronutrient composition is 45% of energy from carbohydrates, emphasising low glycaemic sources, 35% from fat, and 20% from protein. This macronutrient distribution is similar to the average Australian diet, but the GI index is lower. The diet will aim to be as low in GI as practical and achieved by replacing higher GI carbohydrates (e.g., conventional white or wholemeal bread, breakfast cereals, potatoes) with lower GI carbohydrates (e.g., Burgen 'Registered Trademark' grain breads, oats, pasta, Basmati rice). The GI of the low GI/GL diet will be <50 (glucose < 100) and calculated using published data for Australian foods, which has been largely generated by CIB. The diet will emphasise lean sources of protein and restriction of saturated and trans fat (but not total fat). Individual dietary counselling is necessary to identify current dietary patterns, recommend specific changes, and identify barriers and target behavioural change strategies to the individual successfully. This will be accomplished by having the OA educators meet individually with participants in 60 minute sessions, once per week for the first 4 weeks, then fortnightly for the next 8 visits, then monthly for remainder of the year. Participants will be provided with leaflets that outline the carbohydrate choices and the food amounts that constitute one serving. The OA educators will also provide information on the whole diet to ensure energy and overall nutrient balance and be available for telephone queries outside of scheduled visits. To further encourage dietary adherence, key foods will be provided in the form of a hamper (sample bag). All participants will be weighed at each diet visit the same calibrated scale at the laboratory, as frequent weighing has been shown to enhance weight loss significantly. The participants will also be asked to weigh themselves each morning and measure their waist circumference once a week using tools we give them, and record this in their logbooks. They will also be asked to complete a 24 hour recall of their food intake once a week. All of these results will be recorded in a pocket-sized log that the participant will keep for the year. These logs will be reviewed each week at the time of weighing by the OA educators. Logging of behaviour and goals has been shown to significantly enhance compliance and weight loss. At 3, 6 and 12 months, unannounced 24-hour food recall interviews will be conducted in conjunction with collection of 3-day food diaries to assess dietary compliance. Participants who have low adherence (<75%) will receive additional individual booster sessions by the OA educators, in person or by telephone if they are not attending sessions. The behavioural change principles that will be utilised to maximise adherence include the theoretically-grounded principles of decisional balance, social cognitive theory and the stages of change model. Multi-skilled health professional educators with expertise in both the dietary and exercise components of the lifestyle modification program are critical to oversee the intervention and nurture participant perception that these elements are inextricably linked to successful long-term weight control and OA management. ARM 3 – PROGRESSIVE RESISTANCE TRAINING (PRT GROUP) Participants assigned to this group will undergo high intensity PRT for 60-90 minutes, 2 times per week for 12 months, including seated leg press, knee extension, knee flexion, standing hip flexion and hip abduction, using Keiser pneumatic strength training equipment, which allows for low impact, and smooth, continuous progressive loading. Sessions will be conducted in small groups supervised by an experienced exercise physiologist. The specific protocol for the strength training has been successfully used in the REACH study (Lange et al, 2009) by our team and is supported by a large RCT evidence base for the use of PRT in knee OA which we have recently reviewed. Legs will be trained unilaterally (3 sets of 8 reps) to maximise isolation of the muscle groups and training adaptations, as well as to customise loads for asymmetry in strength due to underlying arthritis. Initial resistance will be set at 50% of the baseline 1RM, and increased to 80% of participant’s initial 1RM over the first 4 weeks of training. The resistance will be increased progressively at each session by approximately 3% or the appropriate load in order to keep the training intensity between 15 and 18 (HARD) on the Borg scale of Perceived Exertion, modified as needed for joint pain. ARM 4 – GAIT + DIET + PRT (COMBINED GROUP) Volunteers assigned to this group will receive all the components of the gait training, progressive resistance training and the high protein / low GI diet intervention. Visits to Lidcombe will offer combined training/educational sessions to minimise burden on the subjects in the combined group. We expect that, based on ADAPT study (Messier et al, 2004), each of the intervention arms will be more effective than usual care advice, as was shown in ADAPT with diet and/or aerobic exercise vs. usual care. We anticipate that our interventions will be more effective and sustainable than the ADAPT diet and exercise interventions due to their more targeted approach to the pathophysiology of knee OA than standard weight loss diets and walking exercise, and higher efficacy of DIOGENES-type diet compared to low fat, energy restricted weight loss diet.