Trampolines can be found in many gardens and also in some
playgrounds. They offer an easily accessible vertical motion that
includes free fall. In this work, the motion on a trampoline is modelled
by assuming a linear relation between force and deflection, giving
harmonic oscillations for small amplitudes. An expression for the
cycle-time is obtained in terms of maximum normalized force from the
trampoline and the harmonic frequency. A simple expression is obtained
for the ratio between air-time and harmonic period, and the maximum
g-factor. The results are compared to experimental results, including
accelerometer data showing 7g during bounces on a small trampoline
in an amusement park play area. Similar results are obtained on a larger
garden trampoline, and even larger accelerations have been measured for
gymnastic trampolines.