The purpose of this study was to compare the effect of a10,000 steps per day message and a 30 minutes per day message on physical activity levels in low active, overweight and obese women for 12 weeks. Our results show that the 10,000 step group and the 30 minutes group both had an increase in daily steps at 6 and 12 weeks compared with baseline. However, overweight and obese women accumulated significantly more total steps/day when instructed to walk 10,000 steps per day than when instructed to walk 30 minutes/per day after 12 weeks. In addition, those in the 10,000 steps group significantly increased their amount of walking at 12 weeks compared to baseline, while the 30 minutes group did not. Therefore a 10,000 step goal and immediate feedback from using a pedometer was more effective in increasing physical activity levels in low active overweight and obese women than the 30 minutes/day message.
Consistent with our study, the efficacy of having a step goal and using pedometers daily as a way of increasing walking activity has been demonstrated in a number of studies [12, 15]. The four week study by Hultquist et al  comparing the number of steps accumulated by women instructed to walk 10,000 steps per day with those told to take a brisk 30-minute walk, concluded that women walk more when told to take 10,000 steps per day compared with those instructed to take a brisk 30-minute walk. This study by Hultquist et al  also gave their 30 minutes group a sealed pedometer that was only opened at the end of the week. After four weeks of intervention the 30 minutes group accumulated an average of 8270 ± 354 steps per day and the 10,000 steps group averaged 10,159 ± 292 steps per day. This was similar to our present study where the 10,000 steps group averaged 10,847 ± 1006 steps per day compared to the 30 minutes group who averaged 7786 ± 850 steps per day, after 12 weeks intervention. Another study conducted by our group examined whether the daily use of pedometers could increase physical activity and improve health outcomes in sedentary overweight and obese middle-aged women . Participants were randomized into two groups: The control group wore a sealed pedometer, whilst the pedometer group were given a step goal of 10,000 steps/day, were able to use their pedometers for self-monitoring throughout the day and were asked to record the number of steps on a daily basis for 12 weeks. This previous study showed that the pedometer group significantly increased their steps/day, by 36%, at the end of the 12 weeks, whereas the control group's physical activity levels remained unchanged. This pilot study showed that the combination of having step goals and immediate feedback from using a pedometer was effective in increasing physical activity levels in sedentary overweight and obese women.
A meta-analysis by Bravata et al.  on pedometer use concluded that study participants who have a step goal and were able to record their steps daily, were able to significantly increase their physical activity levels compared to those who did not have a step goal. They found that those who used pedometers, had a step goal and recorded their steps, took an average of 2491 more steps a day compared to those who did not have a step goal. They also found that the step goals groups had an average increase of around 27% when compared to baseline levels. In our study, the 10,000 steps group had an increase of 43% compared to baseline levels whereas the 30 minutes group had an increase of 35% from baseline. It appears that participants in the 10,000 steps group were using their pedometer as a measurement tool as they had a quantitative measure and therefore could monitor their daily physical activity. If they had not achieved the 10,000 steps goal, this could motivate them to undertake more activity to reach the 10,000 steps goal [13, 14]. In comparison, participants in the 30 minutes group were not able to view this information as they were not given a measurement tool for daily use to prompt them to meet their 30 minutes walking goal. Although they were given a daily walking goal of 30 minutes over their normal activity, such a goal was not sufficient to match the physical activity levels undertaken by the 10,000 steps group.
Public health guidelines currently recommend that around 30 minutes of moderate-intensity activity/day on most days of the week provides significant health benefits and can reduce the risk for a range of conditions [8, 9, 11]. Brisk walking for 30 minutes is equivalent to approximately 3500 steps per day [17, 25, 26]. Tudor-Locke et al  suggest that sedentary activity equates to < 5000 steps with 5000-7499 steps being classified as low active. Adding 30 minutes per day (3500 steps per day) to 5025-6231 steps, the baseline means of the two groups in our study, would be close to 10,000 steps per day. Both groups of participants were asked to accumulate approximately 10,000 steps per day. In our study, it appears that those in the 10,000 steps group were better able to comply with the physical activity guidelines with an extra 4616 steps steps/day above baseline steps per day than compared with the extra 2761 steps/day performed above baseline by the 30 minutes group. The 10,000 steps group had a 40% greater increase in steps/day than the 30 minutes group at 12 weeks. Given that 30 minutes of walking is estimated to be equal to approximately 3000-3500 steps, this suggest that the 30 minutes group, on average, did not comply to the 30 minutes/day walking intervention.
There were no significant differences in anthropometric measurements between the 10,000 steps group and 30 minutes group as also shown in other studies . It is possible this could have been as a result of increased energy intake in conjunction with increased physical activity although this is not reflected in the dietary records (Table 2). It is well established however that under reporting of energy intake is widespread in overweight/obese populations [28, 29] and could have occurred here. It is more likely that 10,000 steps/day or an extra 30 minutes/day on top of normal activity is insufficient to achieve weight loss . Although public health guidelines recommend 30 minutes of moderate-intensity activity on most days to maintain good health [8, 9, 11], in order to achieve and maintain weight loss, the US Physical Activity Guidelines Advisory Committee  has now recommended that overweight/obese adults should achieve at least 60 minutes of physical activity on most days of the week. Saris et al  also suggest that moderate intensity exercise of around 60 - 90 minutes (an extra 6000-9000 steps/day), on most days would be necessary for any weight loss to occur. Tudor-Locke et al  suggest that brisk walking for 60 minutes equates to approximately 6,000 steps per day therefore overweight individuals would need to walk an extra 6000+ steps for weight loss. The accumulation of 4616 steps/day by the 10,000 steps group and extra 2761 steps/day accumulated by the 30 minutes group at 12 weeks compared to baseline steps/day may not have been sufficient to observe changes in anthropometric measures . Increasing the steps to at least 12,000 per day for overweight adults would be required to achieve these new guidelines and to encourage weight loss although energy intake also would need to be monitored . Further studies would be required to demonstrate whether pedometers used on a daily basis could encourage overweight individuals to achieve at least 60 minutes of activity on most days or at least 12,000 steps per day to achieve the new recommendations for this group . Therefore, favorable changes in anthropometric measures may be achievable after 12 weeks with higher levels of physical activity.
A study limitation involved using a pedometer without a memory chip. A memory chip enables a daily step tally to be recorded which can indicate how many steps were taken on each day. This would have been useful in order to observe if the 30 minutes group, who despite not being able to see their daily steps, had higher step counts in the first 2-3 days in reaction to the study conditions, as has been shown previously . Changing the type of pedometer for future studies with overweight and obese individuals may be appropriate as a piezo-electric pedometer has been shown to be more accurate for those with a higher BMI than a Yamax Digi-Walker .
All participants in the 30 minutes group were given instructions in the beginning of the study to only record weekly steps and reseal pedometers. They all signed a form to acknowledge that they understood these instructions and would abide by them. However, it was unknown whether there was potential non-compliance with resealing pedometers. It was also unclear whether the 30 minutes group observing their step counts on a weekly basis had an influence on their general activity levels.
Another study limitation involved limited information as to how participants undertook their physical activity. Although levels of activity were recorded, such as walking, moderate intensity and high intensity exercise , there was no indication as to whether the exercise was performed in one bout or in smaller bouts per day. It is recommended that exercise should be undertaken in 10 minute bouts and resistance exercise should also be incorporated twice a week [10, 27] although this was not revealed to the study participants. Also, there can be variability between individuals as one person's exercise intensity can be different to another's even though the same number of steps are taken. The increase in the daily number of steps/day for both groups was mainly through walking activity as indicated by the IPAQ results. Walking has been shown to be the easiest way for individuals to increase physical activity levels and maintain them over the longer term . Self paced walking is the most common physical activity reported by overweight and obese individuals and is preferred due to its low-impact nature and reduced risk of injury [8, 36, 37].
In this study, overweight and obese women accumulated more total steps/day when instructed to walk 10,000 steps per day than when instructed to walk 30 minutes/per day. It appears that having a step goal which can be monitored with the use of a pedometer, where progress can easily be tracked from a reference or baseline point, can act as a motivator  and enables self monitoring [13, 14] which in turn leads to increased physical activity [7, 38]. Setting a step goal in conjunction with the immediate feedback that the pedometer provides may be key motivational factors for increasing physical activity. Other studies have shown that immediate feedback from the pedometers enable participants to set realistic goals, act as an environmental cue, raise awareness of current walking behaviours , to motivate , to self-monitor [13, 39], and to increase walking behaviours [7, 38]. The present findings may be relevant to the wider sedentary overweight and obese population where using a pedometer and having a step goal may provide a promising strategy to increase physical activity.