{'fraction_non_alphanumeric': 0.025223759153783564, 'fraction_numerical': 0.01627339300244101, 'mean_word_length': 4.774647887323944, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Strength balance and low back pain

Low back pain is a common complaint. About two-thirds of an adult population had suffered, suffer or will suffer at least once during their life. Few back disorders have an organic support and thus must enter specific treatment (red flags). On the other hand, a large majority of complaints are without clear aetiology and thus lack efficient treatment, and are at a high risk of chronic development (Burton and Waddell 1998). A huge number of studies have dealt on with the relationships between low back pain and back function (Mayer 1987), clinical observations (Burton and Waddell 1998), individual factors or occupation (Marras 2000). Through functional index, the ratio between trunk flexion and extension strengths has been the most advocated (Mayer 1987). However, few had been done on the studies of the incidence of back function on back pain in large healthy populations. Our objective is to relate the balance of grip to trunk strengths in a large healthy working population. To our knowledge, this balance has never been established on a large number of subjects, while the ability to exert higher forces with the arms then with the trunk could be an explanation of back injuries.