An academic study found that the most common and prevalent musculoskeletal injury in the world is a<unk>  strain. The study further explains that<unk>  strains represented 15% of all injuries per club per season also had a 34% chance of recurrence. Another study showed that a previous<unk>  injury is one of the most cited risks for future injury, with as many as one-third of active individuals experiencing a re-injury within 2 weeks of returning to activity. A meta-analysis article showed evidence that a history of<unk>  injury and being of older age were associated with increased risk of<unk>  strains. One study found that men and master athletes (athletes older than forty) were at an increased risk of<unk>  strains compared with women and younger athletes. Women were approximately 3 times more likely to suffer<unk>  strain than males with the majority of these being non-sporting scenarios. Similarly the average age of non-sporting<unk>  strains are from the ages of 40–60. Many of these non-sporting injuries are sustained during road traffic accidents, slipping, and falling. These results also show that<unk>  strains account for 50% of muscle injuries received by sprinters and are the most common injury in hurdling. One explanation is that older active individuals may be at greater risk due to lower levels of eccentric knee flexor strength compared with their younger counterparts. However, it is unclear whether flexibility serves as a risk factor; this topic should be researched in the future to further understand the relationship between flexibility and risk of injury. Muscle weakness has also been an implication as a predisposing factor for both primary and recurring<unk>  strain injuries. Over a 10-year study more than 51.3% of<unk>  strains occurred during the preseason of athletics. In another study, that analyzed 25 NCAA sports over four years, it was clearly shown that<unk>  strain rates are higher in the preseason. The factors that are being implicated in this trend are the relative deterioration and muscle weakness that occur during the off-season. The<unk> s undergo a complex dynamic process during gait, making it unsurprising that they are frequently injured. They must first contract concentrically during the end of the stance phase in order to bend the knee and allow the foot (along with dorsiflexion at the ankle) to clear the ground. At the end of the swing phase, the<unk> s must eccentrically contract while applying a braking moment to knee extension, then immediately change functions to again concentrically contract and produce hip extension. Studies have shown that “the<unk>  group reaches peak elongation and acts eccentrically at the hip and knee during the late swing phases of running” and that “the<unk> s are most active and develop the greatest torques at the hip and knee during the late swing through midstance phase of running.” Thus, the<unk> s reach their maximum length while attempting to forcefully contract eccentrically and switch functions to immediately produce a concentric contraction, which makes the terminal part of swing phase the most vulnerable for injury. There have been many other proposed predisposing factors to injury. These include muscle weakness, muscle imbalance, poor flexibility, fatigue, inadequate warm up, poor neuromuscular control, and poor running technique. One of the few predisposing factors that most researchers agree upon however is previous<unk>  injury. Brokett et al. (2004) stated that “the athletes most at risk of a<unk>  strain are those with a previous history of such injury” and noted that 34% of the<unk>  injuries were recurrences.” Cameron et al. also found that 34% of injuries recur in the same season. Arnason et al. generalized these numbers, saying that previous injury was in itself an independent risk factor for re-injury.
Pulled hamstring
Deltoid muscle
Abductor wedge
Supertaster
Reflex hammer
Dilator
Azasteroid
Little League elbow