BODY WEIGHT-SUPPORTED TRAINING IN BECKER AND LIMB GIRDLE 2I MUSCULAR DYSTROPHY BENTE R. JENSEN, PhD, 1 MARTIN P. BERTHELSEN, MSc, 1 EDITH HUSU, MD, 2 SOFIE B. CHRISTENSEN, MSc, 1 KIRA P. PRAHM, MD, 2 and JOHN VISSING, MD 2 1 Biomechanics and Motor Control Laboratory, Integrative Physiology, Department of Nutrition, Exercise and Sport, University of Copenhagen, Nørre All e 51, DK-2100 Copenhagen, Denmark 2 Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Denmark Accepted 8 January 2016 ABSTRACT: Introduction: We studied the functional effects of combined strength and aerobic anti-gravity training in severely affected patients with Becker and Limb-Girdle muscular dystro- phies. Methods: Eight patients performed 10-week progressive combined strength (squats, calf raises, lunges) and aerobic (walk/run, jogging in place or high knee-lift) training 3 times/ week in a lower-body positive pressure environment. Closed- kinetic-chain leg muscle strength, isometric knee strength, rate of force development (RFD), and reaction time were evaluated. Results: Baseline data indicated an intact neural activation pat- tern but showed compromised muscle contractile properties. Training (compliance 91%) improved functional leg muscle strength. Squat series performance increased 30%, calf raises 45%, and lunges 23%. Conclusions: Anti-gravity training improved closed-kinetic-chain leg muscle strength despite no changes in isometric knee extension strength and absolute RFD. The improved closed-kinetic-chain performance may relate to neural adaptation involving motor learning and/or improved muscle strength of other muscles than the weak knee extensors. Muscle Nerve 000:000–000, 2016 Patients with severe muscular dystrophies have limited opportunities to perform normal exercise protocols due to weakness. 1–3 Anti-gravity training in a lower body positive pressure (LBPP) chamber is a new training and rehabilitation modality which allows training during off-lifting of body weight (BW). 4,5 No adverse impact on systemic and head cardiovascular parameters has been found with this form of training. 6 We hypothesizes that patients with severe Becker muscular dystrophy (BMD) and Limb Girdle muscular dystrophy type 2I (LGMD2I) have the potential to optimize motor function through motor learning despite reduced muscle strength when the training is performed with BW support in a safe environment. The aim of this study was to investigate func- tional effects of combined strength and aerobic anti-gravity training in severely affected patients with BMD and LGMD2I. MATERIALS AND METHODS Subjects. Eight patients (6 men and 2 women) with an average age of 36 6 4 years, BW of 73 6 5 kg, and height of 176 6 3 cm participated in this training study. Five men were affected by BMD, and 1 man and 2 women had LGMD2I. Inclusion criteria were: genetically verified BMD or LGMD2I; age 18–65 years; and ability to stand and walk, but unable to perform unsupervised physical exercise, such as running, bicycling, or endurance training due to severely affected motor function. Exclusion criteria were: predictable compliance problems to completing the tests and training program; and medical conditions, such as symptoms of impaired cardiac function that could contraindicate physical training or in other ways confound interpretation of the effects of training. For further details regarding the patients, see Berthelsen et al. 5 Oral and written informed consents were obtained from all subjects. The study was approved by the Regional Committee on Health Research Ethics (j.nr. H-3-2011-059) and the Danish Data Protec- tion Agency (j.nr. 2007-58-0015). Intervention Protocol. The study design included a 10-week control period (week -10 to week 0) fol- lowed by 10 weeks of combined individually adapted progressive strength and aerobic training (week 1 to week 10) in an LBPP environment, which offered weight support of up to 80% of nor- mal BW in steps of 1% BW. The LBPP system con- sisted of a treadmill surrounded by a pressure chamber (G-trainer P200, Alter-G, USA). The treadmill and the pressure chamber could be used separately or in combination. The training inter- vention consisted of 40-min sessions performed 3 times weekly. Training Intervention. All training sessions were supervised, and verbal instructions and encourage- ment were given to the patients. Strength training was performed with the treadmill at standstill and relative weight support provided by positive pres- sure in the chamber surrounding the treadmill. Three types of closed-kinetic-chain strength exer- cises were performed: squats, calf raises, and lunges. Three series of each exercise were performed at Abbreviations: BMD, Becker muscular dystrophy; BW, body weight; CK, creatine kinase; H/Q, hamstring-quadriceps; HR max , maximal heart rate; LBPP, lower body positive pressure; LGMD2I, limb-girdle muscular dystro- phy type 2I; MVC, maximal voluntary contraction; RFD, rate of force development Key words: anti-gravity training; Becker and limb-girdle muscular dystro- phy; LBPP; muscle strength; rehabilitation Correspondence to: B. R. Jensen; e-mail: brjensen@nexs.ku.dk V C 2016 Wiley Periodicals, Inc. Published online 00 Month 2016 in Wiley Online Library (wileyonlinelibrary. com). DOI 10.1002/mus.25039 LBPP Training MUSCLE & NERVE Month 2015 1