The mentors were responsible for completing a log book for the adolescent with Down syndrome detailing each exercise performed, the weight lifted, the number of repetitions, and number of sets. The control group participants continued with their usual activities, which may have included leisure and sporting activities but did not include a progressive resistance training program. After the trial was

check details completed, these participants were invited to complete the same program with a student mentor, but no further assessments were conducted. Primary outcome: Muscle strength was assessed using 1 repetition maximum (1RM) force generation tests. These tests established the amount of weight each participant could

lift in a single seated chest press and seated leg press respectively. Single 1RM chest press and leg press tests have high levels of retest reliability (r > 0.89) and demonstrated no systematic change when measured over 3 weeks in adults with neurologic impairment ( Taylor et al 2004). Single 1RM chest press and leg press tests were used as representative measures of upper and lower limb strength, respectively, as they involve the major muscle groups exercising over multiple joints. Secondary outcome: Lower-limb physical function was measured using the Timed Up and Down Stairs test ( Zaino et al 2004). This test was chosen because it is a challenging test of mobility that would be expected to be related to an improved ability to generate muscle force. It has also been implemented previously as an outcome measure in a population

of people with Nintedanib nmr Down syndrome ( Shields et al 2008). Participants were asked to ascend, turn, and descend a flight of stairs as quickly as possible. They could choose any method of traversing the stairs including alternating steps, running up the stairs, or using handrails for support. The time taken to complete the task was recorded in seconds PDK4 using a stopwatch. The test was repeated twice and the fastest time was used in the analysis. Secondary analysis of data from our laboratory has demonstrated moderate retest reliability of the Timed Up and Down Stairs test in adults with Down syndrome (ICC3,1 = 0.74). Upper-limb physical function was measured using the Grocery Shelving Task (Hill et al 2004). Participants started from a seated position 2m from a bench. They were asked to stand up and carry 2 grocery bags, each containing 10 items weighing 410 g (total weight of each bag was 4.1 kg), to the bench. The participants then took the items out of the bag and stacked them onto a shelf at shoulder height. The participants completed the task as fast as possible and the time taken was recorded. Participants were given a practice trial before they completed two timed tests, the average of which was used in the analysis.