Muscle strength imbalances and poor flexibility are frequently described as
risk factors for hamstring injury. Preventive strategies include eccentric
exercises, but the influence of field eccentric exercises on these risk
factors remains unclear. We investigated the influence of a field hamstring
eccentric program on hamstring strength and flexibility. Twenty-seven
amateur athletes were randomly assigned to an intervention (n=13) or
control group (n=14). In the intervention group, participants were
involved in 15 sessions of four eccentric exercises. Peak torque,
hamstring-to-quadriceps ratios, passive and active flexibility were
analyzed. No significant modifications of strength, passive or active
flexibility were observed in the control group (p>0.05). Hamstring
eccentric peak torque (+7.1%) and functional
hamstring-to-quadriceps ratios (9.3%) were significantly increased
(p<0.05) in the intervention group, but not concentric strength
(p<0.05). Passive straight leg raise was significantly increased by
11.4° (+12.7%, p<0.001), but not active
flexibility (+3.1%, p>0.05). In conclusion, a 6-week
eccentric program, including four field exercises for hamstring muscles, is
an effective method of improving eccentric strength, functional ratios and,
especially, passive flexibility. As this program may be easily implemented
in a real-world context, this association of multiple eccentric exercises
might be useful in an injury prevention strategy.