Erin A. Dannecker

Fear of pain, not pain catastrophizing, predicts acute pain intensity, but neither factor predicts tolerance or blood pressure reactivity: An experimental investigation in pain-free individuals

Previous studies of the Fear‐Avoidance Model of Exaggerated Pain Perception have commonly included patients with chronic low back pain, making it difficult to determine which psychological factors led to the development of an “exaggerated pain perception”. This study investigated the validity of the Fear‐Avoidance Model of Exaggerated Pain Perception by considering the influence of fear of pain and pain catastrophizing on acute pain perception, after considering sex and anxiety. Thirty‐two males and 34 females completed the State‐Trait Anxiety Inventory, the Fear of Pain Questionnaire, and the Coping Strategies Questionnaire. Subjects underwent a cold pressor procedure and tolerance, pain intensity, and blood pressure reactivity were measured. Sex, anxiety, fear of pain, and pain catastrophizing were simultaneously entered into separate multiple regression models to predict different components of pain perception. Tolerance was not predicted by fear of pain, pain catastrophizing, or anxiety. Pain intensity at threshold and tolerance were significantly predicted by fear of pain, only. Blood pressure reactivity to pain was significantly predicted by anxiety, only. These results suggest that fear of pain may have a stronger influence on acute pain intensity when compared to pain catastrophizing, while neither of the factors predicted tolerance or blood pressure reactivity.

Sex differences in delayed onset muscle pain

Objective: In contrast to the research using typical experimental pain stimuli, there is no consensus that women are more sensitive to delayed onset muscle pain than men. The purpose of this study was to examine sex differences in delayed onset muscle pain with use of a quantified stimulus intensity and multidimensional and valid pain measures. Methods: Ninety-five participants (49.5% women) completed eccentric exercise and then returned to the laboratory at 24 and 48 hours postexercise. The same relative intensity of the eccentric exercise was administered to women and men based on their eccentric strength. Results: The occurrence of muscle pain was confirmed by increases in intensity, F 2, 182 = 162.28, P<0.01, η 2 = 0.64, and unpleasantness, F 2, 182 = 204.03, P < 0.01, η 2 = 0.69, and standardized pain ratings, F 2, 180 = 67.44, P < 0.01, η 2 = 0.43. The affective ratios indicated that the muscle pain was more unpleasant than intense. No sex differences were detected except that men reported higher affective ratios than women, F 1, 92 = 4.06, P < 0.05, η 2 = 0.04. Discussion: The absence of higher muscle pain ratings in women than men in this investigation resembles a review of the delayed onset muscle soreness and pain literature. However, the findings contradict a few other acute muscle pain investigations, in which actual muscle tissue damage was not induced by eccentric contractions. Additional research is required to identify the parameters that influence the detection of sex differences.

Critical issues in the use of muscle testing for the determination of sincerity of effort.

Over the past 20 years, there have been numerous attempts to identify methodologies that are capable of the determination of sincerity of effort during muscle testing. The ensuing paper reviewed this literature and drew several conclusions. Injured patients and healthy volunteers do produce less force and more variable force while performing submaximal contractions than maximal contractions. However, submaximal efforts during strength testing can be reproduced and the use of force variability is not adequate to distinguish sincerity of effort. Visual examination of the shape of force output curves is also not adequate for distinguishing sincerity of effort. Furthermore, much of the research using strength ratios, difference scores, and an assortment of different parameters derived during strength testing has not established reliable and clinically useful methods of differentiating effort levels. Methods examining motion variability, radial/ulnar force output ratios, difference scores of eccentric-concentric ratios, and electromyography offer some promise, but numerous critical issues need to addressed. The use of the coefficient of variation, for example, is statistically untenable given the number of trials appropriate for clinical samples. Several studies have inadequate sample size to number of variable ratios. Many studies have questionable or at least unknown generalizability to patient samples and actual functional capacity. It is critical that other explanatory variables such as fear of injury, pain, medications, work satisfaction, and other motivational factors be considered. It is our opinion that there is not sufficient empirical evidence to support the clinical application of muscle testing to determine sincerity of effort.

Validation of a Stages of Exercise Change Questionnaire

Abstract The purpose of this study was to examine evidence for the validity of a stages of change measure of the Transtheoretical Model for exercise behavior. Participants were 152 university students (53.3% women, 71.6% Caucasian, M age = 19.18 years) who completed processes of change, self-efficacy, decisional balance, stages of change, and exercise behavior questionnaires as well as a maximal treadmill test. Participants in the action and maintenance stages had the highest strenuous (PC/C/P < A/M) and moderate (PC/C < A/M) self-reported exercise behavior. Those in the maintenance stage had the highest estimated aerobic fitness (PC/P < M). The differences between the early stages (PC, C, and P) and the later stages (A and M) as described by the first function were primarily due to the behavioral process of change. The differences between the extreme stages (PC and M) and the middle stages (C, P, and A) were due to the experiential processes of change and the pros of decisional balance. The hypothesized patterns ofstage differences were partially supported. Failure to obtain full support may have been due to methodological issues or inherent difficulties in detecting evidence for the validity of stages of change measures.

Sex Differences in Exercise-Induced Muscle Pain and Muscle Damage

UNLABELLED There is uncertainty about sex differences in exercise-induced muscle pain and muscle damage due to several methodological weaknesses in the literature. This investigation tested the hypothesis that higher levels of exercise-induced muscle pain and muscle damage indicators would be found in women than men when several methodological improvements were executed in the same study. Participants (N = 33; 42% women) with an average age of 23 years (SD = 2.82) consented to participate. After a familiarization session, participants visited the laboratory before and across 4 days after eccentric exercise was completed to induce arm muscle pain and muscle damage. Our primary outcomes were arm pain ratings and pressure pain thresholds. However, we also measured the following indicators of muscle damage: arm girth; resting elbow extension; isometric elbow flexor strength; myoglobin (Mb); tumor necrosis factor (TNFa); interleukin 1beta (IL1b); and total nitric oxide (NO). Temporary induction of muscle damage was indicated by changes in all outcome measures except TNFa and IL1b. In contrast to our hypotheses, women reported moderately lower and less frequent muscle pain than men. Also, womens arm girth and Mb levels increased moderately less than mens, but the differences were not significant. Few large sex differences were detected. PERSPECTIVE Lower muscle pain among women than men was detected with corresponding, but nonsignificant sex differences in other muscle damage indicators. Methodological advances may have improved alignment of these results with the nonhuman animal findings. This line of research continues to show exceptions to the generalization that women experience greater pain than men.

Pressure and activity-related allodynia in delayed-onset muscle pain.

ObjectivesMuscle pain from different activities was tested with the muscle pain expected to vary in ways that may clarify mechanisms of activity-induced exacerbation of myofascial pain. MethodsParticipants [N=20; 45% women; 23 y old (SD=2.09)] consented to participate in a 6 session protocol. Bilateral muscle pain ratings and pressure pain thresholds (PPTs) were collected before and for 4 days after lengthening (ie, eccentric) muscle contractions were completed with the nondominant elbow flexors to induce delayed-onset muscle pain. The muscle pain ratings were collected with the arms in several conditions (eg, resting, moving, and contracting in a static position) and PPTs were collected with the arms. ResultsIn the ipsilateral arm, muscle pain ratings at rest and during activity significantly increased whereas PPTs significantly decreased after the eccentrics (&eegr;2s=0.17 to 0.54). The greatest increases in pain occurred during arm extension without applied load, in which there was more stretching but less force than isometrics. In the contralateral arm, neither muscle pain nor PPTs changed from baseline. DiscussionThese results resemble earlier electrophysiology studies showing differential sensitization across stimuli and support that increased depth of information about aggravating activities from clinical patients is needed.

Pain During and Within Hours After Exercise in Healthy Adults

Literature on the pain relieving effects of exercise has been reviewed several times. It is equally important to review the literature on the pain-inducing effects of exercise. Indeed, exercise professionals, health care providers, and exercisers must grapple with the fact that exercise can both induce and reduce pain. The objective of this review was to synthesize our current understanding of exercise-induced pain and inspire advanced research. We searched the PubMed database for publications since 2000 about healthy human participants. Disease-specific reviews of the effects of exercise are available elsewhere. The results of our literature review verified that many different modes, intensities, and durations of exercise can induce pain in healthy people. Another important point is that pain can occur within a few hours after eccentric contractions, which should be considered relative to the construct of delayed-onset muscle soreness. In addition, the studies supported that exercise can be painful in diverse muscle groups. Yet another point illuminated by the literature is that different pain measures do not always change in similar directions and magnitudes after exercise. Therefore, our review confirms that a wide variety of exercises can be painful—even for healthy people. We wonder how many exercise professionals and health care providers regularly and appropriately measure exercise-related pain or consider such pain in their exercise recommendations. We also question if exercise-related pain affects exercise behavior in healthy people as it has been shown to do in people with chronic illnesses. Additional research is needed to improve both exercise recommendations and exercise behavior.

Appraisals of pain from controlled stimuli: relevance to quantitative sensory testing.

OBJECTIVE Sensory testing has been advocated for the diagnosis, prognosis, and outcome evaluation of pain patients, but responses to controlled stimuli have not been well correlated to clinical pain. As an initial step for improving the clinical relevance of sensory testing, this investigation compared appraisals of and responses to controlled pain stimuli. DESIGN A prospective within subjects design was used. METHODS Heat, ischaemic, and delayed-onset muscle pain were induced in the upper extremity of 44 participants (47.7% women) during four experimental sessions. RESULTS The threat of heat and ischaemic pain was higher than delayed-onset muscle pain (F(2,86) = 5.30, p<.01, eta(2) = .11). Threat, challenge, predictability, and controllability were related to heat pain most consistently. The affective-sensory ratios of ischaemic and delayed-onset muscle pain resembled those of clinical pain and were higher than heat pain (F(2,84) = 11.64, p<.01, eta(2) = .22). Delayed-onset muscle pain meaningfully affected daily activities, which correlated to delayed-onset muscle pain ratings (rs = .60-.68, ps <.001). CONCLUSIONS Heat stimuli may be well suited for instructional manipulations of appraisals to improve the clinical relevance of quantitative sensory testing and delayed-onset muscle pains effects on daily activities are clinically relevant.

The Effect of Fasting on Indicators of Muscle Damage

Many studies have tested the consumption of foods and supplements to reduce exercise-induced muscle damage, but fasting itself is also worthy of investigation due to reports of beneficial effects of caloric restriction and/or intermittent fasting on inflammation and oxidative stress. This preliminary investigation compared indicators of exercise-induced muscle damage between upper-body untrained participants (N=29, 22yrs old (SD=3.34), 12 women) who completed 8h water-only fasts or ate a controlled diet in the 8h prior to five consecutive laboratory sessions. All sessions were conducted in the afternoon hours (i.e., post meridiem) and the women completed the first session while in the follicular phase of their menstrual cycles. Measures of muscle pain, resting elbow extension, upper arm girth, isometric strength, myoglobin (Mb), total nitric oxide (NO), interleukin 1beta (IL1b), and tumor necrosis factor alpha (TNFa) were collected before and after eccentric contractions of the non-dominant elbow flexors were completed. The fasting groups loss of elbow extension was less than the post-prandial group (p<.05, eta(2)=.10), but the groups did not change differently across time for any other outcome measures. However, significantly higher NO (p<.05, eta(2)=.22) and lower TNFa (p<.001, eta(2)=.53) were detected in the fasting group than the post-prandial group regardless of time. These results suggest intermittent fasting does not robustly inhibit the signs and symptoms of exercise-induced muscle damage, but such fasting may generally affect common indirect markers of muscle damage.

Osteoarthritis and Social Embarrassment

Musculoskeletal pain from osteoarthritis (OA) is a prevalent concern for older adults. Despite recommendations from providers to be physically active, some people with OA fear physical activity and must decide whether it is safe or harmful to undertake physical activity. In this article, we examined the narratives of 10 people living with OA knee pain and the roles that pain and embarrassment played in their activity-related behavior. When asked about their physical activity, 6 of the 10 participants reported some type of embarrassment-related experience. Responses fell into two key categories: (a) embarrassment-related experience from engaging in activity or (b) embarrassment-related experience from avoiding activity. These categories contained subgroups of those seeking to avoid embarrassment and those seeking to avoid pain. Response clusters helped to contextualize the activity behavior of people with knee OA pain as it relates to social identity by providing examples of individuals resisting life disruption.