Good to know
When holding the SPARROWBAG®, do not only hold the textile, but also get hold of some of the sand contained. By shaking the bag, filler material can easily be spread uniformly inside it. Take care to keep a correct back posture. Back should be straight when performing an exercise, or slightly bent, to avoid spine overload.
For trainers
Motor muscles
elbow (up/flexor, down/extensor) m.biceps brachii, shoulder (up/extension, horizontal adduction, down/flexion, horizontal adduction) m.latissimus dorsi, m.teres major, m.pectoralis major, m. deltoideus back part, m.infraspinatus, m.teres minor, scapula (up/adduction-retraction, down/abduction-protraction) mm.rhomboidei, m.trapezius
Stabilizers
legs (knee flexors, buttock muscles, adductor group), m.quadriceps- and rectus femoris), body (abdominal muscle group), m.erector spinae, shoulder articulation (rotator sheath) scapula (m.serratus anterior, mn.rhomboidei, m.trapezius lower part), forearm (wrist flexors)