Impact loading training in people with chronic obstructive pulmonary disease: a pilot study examining the feasibility and tolerance of this intervention and its effect on bone health

The total duration of the intervention period will be 40 weeks. For the first 8 weeks of the intervention period participants will complete a standard Pulmonary Rehabilitation Program (PRP). This program runs for an average of 8 weeks, with two 90-minute classes per week and includes all core components recommended by the international guidelines. These are aerobic and resistance exercise, psychosocial support, disease-specific education which includes information on self-management strategies. Each class is run by a physiotherapist in the hospital outpatient area and has up to 12 participants per class. As part of standard PRP all participants will be given a home exercise program (HEP) and exercise training log. As per standard practise the participants will be encouraged to complete the HEP 3 to 5 times a week whilst attending the PRP and they are encouraged to continue with the HEP after they have completed the PRP (as a life-long maintenance strategy). Exercises prescribed during the PRP (and HEP) are individualised for each participant but generally include a 20-30 minute walking program prescribed using the results of a 6-minute walk test together with functional lower limb exercises, such as steps ups and sit to stands and functional upper limb exercises using light hand weights (i.e. 500g-2kg) such as forward and upward punches. By completion of the PRP, patients are usually performing 3 sets of 10 repetitions of these functional exercises. In order to maximise musculoskeletal health and function, participants will be provided with calcium (1,000 mg/day) and vitamin D (800 IU/day) supplements, in oral tablet form, throughout the 40-week intervention period. Participants will be asked if they have previously taken or are currently taking calcium and Vitamin D supplements. In addition to the usual PRP and HEP, participants will also undertake a program of targeted lower limb resistance exercises and impact loading exercises. The targeted lower limb resistance exercises will be completed in the PRP class (weeks 1-8) and will take between 10 and 20 minutes to complete. These exercises are specifically designed to improve gluteal, hamstring, quadriceps and calf muscle strength in preparation for the impact loading exercises. The exercises will include calf raises, knee flexion and extension using a multigym, seated knee flexion/extension with theraband if unable to use the multigym, squats and lunges. The target for each exercise is 1-3 sets for 8-10 repetitions (8-10 repetition maximum [RM] which is roughly equivalent to 75-80% of the 1RM). These exercises will be interspersed using a circuit based approach with the other exercises within the standard PRP session and will be closely supervised by a physiotherapist. The impact loading exercises will commence in week 5 of the PRP. These will be individually prescribed for each participant using the current recommendations for exercise prescription for the prevention and management of osteoporosis. Using the Exercise and Sports Science Australia (ESSA) position statement (Beck et al, 2017), the intensity, frequency and sets/repetitions of each impact loading exercise will be tailored taking into account the participants existing bone health status, co-morbidities and functional/clinical risk factors for falls and fractures. Each participant will be categorised as low, moderate or high risk for a fragility fracture and the prescription of the impact loading exercises will be modified accordingly. All modifications to the exercise prescription detailed below will be recorded. Following weeks 1-4, the remainder of the intervention period is divided into Block 1 (Weeks 5-8), Block 2 (Weeks 9-16), Block 3 (Weeks 17-28) and Block 4 (Weeks 29-40). In Block 1 the participants will commence two impact loading exercises; bounding over hurdles and drop jumps. The target will be to complete 2 sets of 10 repetitions (1-2 minutes rest between each set). These will be completed during the PRP class under the supervision of a physiotherapist. In weeks 6 and 7 of Block 1, the participants who are tolerating the exercises, with no reports of pain or safety concerns, will be asked to complete an extra two sessions of the exercises unsupervised at home. The first home-based session will be supervised by a physiotherapist in the participant’s home. A suitable area will be established in the patient’s home environment to complete the exercises taking into account safety as well as a consistent floor surface. In addition to a consistent surface to complete the exercises at home, participants will be asked to wear the same or similar footwear every time they complete the exercises. The surface and footwear will be recorded. In Block 2 participants will continue with the impact loading exercises prescribed in Block 1 and will increase the number of target sets from 2 to 3. These will be completed four times per week at the participant’s home unsupervised. At the beginning of Block 3 the participants will be visited by a physiotherapist at home and their impact loading exercises will be progressed to include an extra exercise; hopping on one leg. In Block 3 the three impact loading exercises will be completed with a target of completing 3 sets of 10 repetitions (1-2 minutes rest between sets) four times per week in the participants’ home unsupervised. At the beginning of Block 4 the participants will be visited by a physiotherapist who will again progress their exercises and add a new exercise; leaping. In Block 4 the four impact loading exercises will be completed unsupervised in the participants home, four times per week, with a target of achieving 3 sets of 10 repetitions (1-2 minutes rest in between each set). If difficulties during impact loading training are reported, despite exercise modifications, the individual’s participation in the intervention will be discontinued. However, they will be asked to attend all remaining assessment sessions so their data can be analysed according to the intention-to-treat principle. Participants will be regularly asked if they are experiencing any issues with stress continence during the impact loading exercises and offered a referral to a continence physiotherapist clinic if this is reported. Measures related to the primary aim (i.e. feasibility and tolerance) will be recorded throughout the duration of the study using exercise logs and scheduled contact points with the participants. The exercise prescription and any modifications to the exercises will be recorded in these logs. From Block 2, participants will receive fortnightly phone calls from the primary investigator. To assess feasibility of the study protocol, data will be recorded pertaining to recruitment, withdrawal and completion, as well as adherence to the prescribed sessions (using an exercise log, completed by the participant). Participants will also be asked about their adherence to taking the calcium and Vitamin D supplements. Tolerance of the intervention will be assessed and monitored by; 1. Asking participants to rate symptoms of lower limb joint discomfort / pain, breathlessness and perceived exertion, at the completion of each exercise session, using validated scales (i.e. BORG dyspnoea and the visual analogue scale [VAS]). 2. Asking participants to immediately contact the primary investigator if they experience any adverse events, such as a fall, throughout the duration of the study. These data will be recorded by the primary investigator. These will be classified as minor (self-resolving) or major (required medical intervention). 3. On study completion, seeking feedback from participants regarding their experiences.