The purpose of this study was to investigate the effects on leg muscular performance from whole-body vibration exercise. Literature search was performed on the databases Pubmed, Cinahl, ISI web of science (Sci-expanded, SSCI) and Embase (Rehab & Physical Med). Rating of 19 relevant studies was performed (14 on long-term exercise and five on short-term exercise) using a score system for the methodological quality. Several randomized-controlled trial studies of high to moderate quality show similar improvements from long-term regimen on muscular performance in the legs after a period of whole-body vibration exercise. As there were few studies on short-term exercise and as they had no control groups, the same convincing improvements regarding muscular performance were not achieved. Preliminarily, there is strong to moderate evidence that long-term whole-body vibration exercise can have positive effects on the leg muscular performance among untrained people and elderly women. There is no clear evidence for effects on muscular performance after short-term vibration stimuli.

PurposeThis study investigates how small firms develop preferences for varying levels of alliance partner diversity by applying a behavioral perspective.Design/methodology/approachData were collected via an original survey administered by the Swedish National Bureau of Statistics (SCB) of 1,026 Swedish firms with 50 employees or less. Hypotheses were tested by specifying a series of fractional response regressions.FindingsThe results show a U-shaped relationship between experienced and preferred alliance partner diversity in small firms and further show moderating effects of firm age, prior growth and environmental dynamism. The findings suggest that preferences towards diverse alliance portfolios in small firms may arise, not only from well-informed deliberate strategic thinking based on prior experience, but also as a consequence of cognitive bias.Practical implicationsThe findings suggest that (1) small firms considering a wide variety of alliance partners should carefully investigate whether they are, in fact, capable of mastering a highly diverse alliance portfolio or if they are overconfident novices. (2) Holders of homogenous alliance portfolios should recurringly investigate whether homogeneity is due to informed strategy or inertia.Originality/valueThis study contributes to the literature on alliance partner diversity and behavioral alliance portfolio configuration by shedding light on the learning mechanisms that shape alliance portfolio strategies of small firms by explicating the complexity of how different experience levels of partner variety affect current alliance portfolio preferences.