Individuals participating in vigorous activity, in synchrony with others have been shown to exhibit a significantly higher endorphin release than performing the same activity alone. This finding, dubbed the Synchrony Effect (SE), has been repeatedly found in studies involving rowing from 30-35 minutes (Cohen et al., 2010; Sullivan & Rickers, 2013). Synchronized activities of a much shorter duration have been shown to affect the behavior of participants (Vandesolo et al, 2010). The current study was designed to see if the SE could be seen in shorter rowing duration. A sample of 54 individuals rowed in pairs on ergometers in counterbalanced 10 minute sessions of individual and group (synchronized) exercise. Pain threshold was taken immediately prior to and after the exercise, using an algometer, to indicate endorphin activity. A paired samples t-test comparing pre to post changes in pain threshold showed no difference between the conditions (t (1, 53) = 0.87, p > .05) failing to support the SE. It appears that activities longer than 10 minutes are needed to induce the SE, although shorter duration synchronized activities may still affect social outcomes. An alternative explanation may lie in the nature of the samples in the SE studies. Prior studies typically used samples of experienced rowers, who may be more capable of optimizing synchrony than the non-rowers in the current study. It may be that a finer degree of synchrony than the current sample of non-experienced rowers could maintain is required for the SE.