# The Effects of Exergames on Muscle Architecture: A Systematic Review and Meta-Analysis
## 4 Discussion  
To the authors' knowledge, this systematic review is the first systematic review focusing particularly on the effects of exergames on the architectural parameters of the skeletal muscles in humans. Based on studies identified to have a fair level of quality [110; 111], 12 weeks of virtual dance exercises (Dance Central game for Xbox 360(\({}^{\text{\textregistered}}\)) has a medium effect on increasing the quadriceps femoris muscle cross-sectional area. Likewise, 12 weeks of virtual dance exercises (Dance Central game for Xbox 360(\({}^{\text{\textregistered}}\)) has a medium effect on increasing the quadriceps femoris muscle cross-sectional area based on a study with fair-level quality [110]. Additionally, a good-quality study [109] pointed out that four weeks of virtual balance training (via using the ProKin system) was significantly more effective than home-based balance training with the Swiss ball and conventional balance training in increasing paraspinal muscle size at the L3-L4 level and multifidus muscle size at the L4-L5 level in football players with chronic lower back pain. More specifically, the four weeks of virtual balance training [109] led to 14.55-46.81% increments in the paraspinal muscle cross-sectional areas (psoas major: 25.58-26.19%, quadratus lumborum: 41.67-46.81%, multifidus: 44.23-43.40%, erect spinae: 14.55-14.63%) and 6.4-8.46% increments in multifidus muscle thickness (Supplementary Table S3). On the other hand, meta-analyses measuring the impacts of twelve weeks of exergame interventions (Nintendo Wii Fit Plus(\({}^{\text{\textregistered}}\) + balance platform [107] and Dance Central game for Xbox 360(\({}^{\text{\textregistered}}\) + Kinect [108]) on gastrocnemius muscle architectural parameters, including fascicle length, muscle thickness, and pennation angle, in community-dwelling older women could not detect any positive medium or large effects of these exergames on the medial gastrocnemius muscle architectural parameters based on the fair-good-level studies [107; 108]. From the perspective of the effects of 12 weeks of virtual dance exercises (Dance Central game for Xbox 360(\({}^{\text{\textregistered}}\)), medium effects on the increase in muscle size of the quadriceps femoris and hamstrings of community-dwelling older women were detected by the meta-analyses of this study. Moreover, the effect size of 12 weeks of virtual dance exercises on quadricp muscle size increments in community-dwelling older and filler women was large (\(g\) = 0.92) (Figure 4). When considering older people, falling is one of the major reasons for mortality, loss of independence, or severe health problems [112; 113; 114]. Thirty per cent of community-dwelling people 65 years old or older fall every year [115; 116]. Small muscle size was defined as an indicator of a higher risk of falls in community-dwelling older people [39; 40; 117; 118]. Therefore, 12 weeks of virtual dance exercises (Dance Central game for Xbox 360(\({}^{\text{\textregistered}}\)) can be used as a complementary therapy in fall prevention programs for the elderly due to its medium to large effects on increasing cross-sectional areas of the hamstrings and quadriceps femoris. Additionally, [PERSON] and colleagues [109] found significantly favourable increments in the paraspinal and multifidus muscle sizes from the virtual balance training as comparedto combined physical rehabilitation, which included balance exercises using a Swiss Ball, or conventional balance training. Previously, balance training with a Swiss Ball was considered the golden standard for balance training and enhancing the strength of core muscles [119]. However, four weeks of virtual reality balance training using the ProKin system led to percentage increments approximately two times higher in the cross-sectional areas of the individual paraspinal muscles (ereactor spinae, multifidus, psoas major, and quadratus lumborum) than four weeks of combined physical therapy, which included a Swiss Ball balance training (Supplementary Table S3).