Parachute Landing Research Articles

The Biomechanics of the Knee during the Parachute Landing Fall

Because anterior knee pain syndrome is common in young paratroopers, we studied the role of the extensor mechanism in deceleration during the parachute landing fall (PLF) and the extent of knee flexion resulting from use of proper and variant landing styles. The subjects were novice paratroopers. Data were gathered by electromyography and by cinematography. At impact, a period of myoelectric silence was found that increased during training. Knee flexion angles varied from 130 degrees in the proper PLF to a low of 110 degrees in the toes-knees-nose PLF and to a high of 160 degrees in the hypergenuflexion PLF. The improper PLFs had a duration of deceleration shorter than that of a proper PLF, with maximal knee flexion occurring later in the landing act. Our results give direction to more specific lower-body training.

A Study of the Influence of Body Weight and Height on Military Parachute Landing Injuries

The weights and heights of 1,880 male military parachutists were recorded, and landing injury rates were calculated according to the weights and heights of the jumpers. Only the weight significantly influenced the injury rate. The set of data (weight, injury rate) are best fitted with a parabola of the form: y = 43.14 - 1.22x + 0.01x2. The concept of the maximal operating weight of a parachute is discussed with its implications for medical standards and for jumps with extra equipment.

Parachuting injuries: a study of 110,000 sports jumps.

A study was undertaken to examine the type, location, incidence and mechanism of injury sustained by amateur parachutists in Denmark during a five-year-period. A total of 110,000 parachute jumps resulted in six (0.005%) fatalities and 155 (0.14%) cases, requiring medical treatment. The latter group sustained 176 injuries of which 36.9% were significant soft tissue lesions and 63.1% fractures. Landing is the most dangerous part of the parachuting procedure, causing 83.8% of the accidents, while 9.3% were caused by faults during opening of the parachute. Based on the injury pattern, some modifications to the procedures and equipment are mentioned. A simplification of the parachute landing fall and the development of safer parachutes may reduce the incidence of casualties. An enforcement of the present regulations is necessary as many injuries are the result of noncompliance with regulations due to ignorance, inexperience or carelessness.

Aircrew helmet protection against potential cerebral concussion in low-magnitude impacts : Norman, R.W., et al Aviation, Space and Environmental Medicine, Jun 1979, 50.6, 553–561

The response of the Gentex DH-151 (contact type) and Gentex 411 (suspension type) aircrew helmets to low-magnitude impacts, such as those sometimes encountered during cockpit buffeting, in ejection, and in parachute landings, was studied to augment the data base on helmet performance. The helmets, mounted on a Hodgson headform, were dropped on the crown and rear at impact velocities up to 4.97 m/s. Acceleration time histories were tape recorded and digitized and Gadd Severity Indices (GSI), among others, were calculated from the resultant acceleration curve. Both helmets kept the GSI below predicted concussion thresholds at 4.97 m/s and were considered to perform well on initial impacts. On second impacts, the GSI rose considerably because the shell and liner of the DH-151 cracked and the suspension of the "141" stretched during the first blow. Improvement of the multiple impact performance of both helmets appears desirable, although the suspension helmet performed slightly better than the contact helmet with respect to the criterion used.

The spine in sport and veteran military parachutists.

Spinal injuries and symptoms were studied in 109 ex-military parachutists and 112 sport (free fall) parachutists by means of postal questionnaires. 46 ex-military parachutists aged 50 years or over had a radiological examination of the lumbar spine and 58 sport parachutists had a radiological examination of the cervical spine as part of the survey. A history of back pain was significantly (P<0.01) associated with body weight in sport parachutists but not with the number of descents or with the subject's age. In the older ex-military group neither age, weight, nor the number of descents was significantly associated with backache. Of those ex-military parachutists x-rayed, 10 (21.7%) were found to have vertebral body fractures (most frequently at D12), and 8 of these were unaware of these lesions. Vertebral fractures caused no disability and did not permanently curtail parachuting activities in either the sport or ex-military group. Of the ex-military parachutists x-rayed, 84.7% had lumbar disc degeneration of all grades of severity, 17.4% had moderate changes, and 10.8% had severe changes. The frequency of moderate and severe disc degeneration was significantly related to age but not to body weight or to the number of descents. Spondylolysis was found in 2 subjects (4.3%) and spondylolisthesis unassociated with spondylolysis in 4 (8.7%). Spondylolisthesis was always associated with a history of back pain.A low prevalence of radiological cervical intervertebral disc degeneration of all grades of severity of 8.7% was found among the free fall parachutists (mean age 33 years). 2 cases of cervical vertebral body fracture were seen, one related to a parachute landing injury and the other to a parachute opening injury. This study does not implicate parachuting as a cause of intervertebral disc degeneration, either cervical or lumbar, nor as a cause of spondylolysis or spondylolisthesis. Serious long-term disability from pain appears to be uncommon among parachutists despite the frequency of the spinal trauma they sustain.

Evaluation of entry and terminal deceleration systems for unmanned Martian landers

Entry and terminal deceleration systems for unmanned Martian landers, discussing parachute landing and lifting entry vehicles