Letter to the editor of Pain about Gemma Ford and David Finn, Clinical correlates of stress-induced analgesia: evidence from pharmacological study. Pain 2008;140:3-7

Whip use by jockeys in a sample of Australian Thoroughbred races--an observational study

The use of whips by jockeys is an issue. The current study viewed opportunistic high-speed footage of 15 race finishes frame-by-frame to examine the outcomes of arm and wrist actions (n = 350) on 40 horses viewed from the left of the field. Any actions fully or partially obscured by infrastructure or other horses were removed from the database, leaving a total of 104 non-contact sweeps and 134 strikes. For all instances of arm actions that resulted in fully visible whip strikes behind the saddle (n = 109), the outcomes noted were area struck, percentage of unpadded section making contact, whether the seam made contact and whether a visible indentation was evident on impact. We also recorded use of clockwise or counter-clockwise arm action from each jockey's whip, whether the whip was held like a tennis racquet or a ski pole, whether the hind leg on the side of the impact was in stance or swing phase and whether the jockey's arm was seen traveling above shoulder height. The goal of the study was to characterize the area struck and the visual impact of whip use at the level of the horse. We measured the ways in which both padded and unpadded sections of the whip made impact. There was evidence of at least 28 examples, in 9 horses, of breaches of the whip rules (one seam contact, 13 contacts with the head, and 14 arm actions that rose above the height of the shoulder). The whip caused a visible indentation on 83% of impacts. The unpadded section of the whip made contact on 64% of impacts. The results call into question the ability of Stewards to effectively police the rules concerning whip use and, more importantly, challenge the notion that padding the distal section of whips completely safeguards horses from any possible whip-related pain.

The relation between sleep and pain among a non-clinical sample of young adults

Poor sleep is linked to poorer daily functioning and increased risk of psychiatric symptoms. With respect to pain, the relation is bi-directional; poor sleep exacerbates pain, while greater pain adversely affects sleep. Moreover, perception of pain is subject to cognitive-emotional processes. Surprisingly, no data are available from non-clinical samples of young adults. The aim of the present study was therefore to investigate the relation between sleep and pain as a function of quality of life and depressive symptoms in young adults. The direction of influence between sleep and pain was statistically tested with two different structural equation models (SEMs). A total of 862 participants (639 women, 223 men; mean age: 24.67; SD = 5.91) completed a series of validated self-report questionnaires assessing sleep, quality of life, depressive symptoms and cognitive-emotional elaboration of pain. Sleep, pain, quality of life, and depressive symptoms were interrelated. The first SEM suggested both a direct and an indirect influence of pain on sleep, whereas the second SEM suggested that sleep had only an indirect influence on pain. Irrespective of the SEM, the relation between sleep and cognitive-emotional elaboration of pain was mediated by quality of life and depressive symptoms. For a non-clinical sample of young adults, findings did support the bi-directional relation between poor sleep and increased cognitive-emotional elaboration of pain, though other cognitive-emotional processes such as depressive symptoms and quality of life should be taken into account.