Practice, Education, and Further Research The results of the 4 studies included in this critically appraised topic demonstrate that hydration status does not change physiological adaptations in plasma volume, internal body temperature, and skin temperature. While heat acclimation protocols can vary, the
Yasuki Sekiguchi, Erica M. Filep, Courteney L. Benjamin, Douglas J. Casa and Lindsay J. DiStefano
Bryan L. Riemann, Nancy Caggiano Tray and Scott M. Lephart
To determine the physiological adaptations that might occur with a 4-week unilateral multiaxial training program in lower leg kinesthesia, peak torque, and postural control.
True experimental pretest-posttest control-group design.
26 healthy, active subjects (14 men, 12 women).
Subjects were assigned to an experimental or control group. The experimental group performed multiaxial coordination training 3 days/wk for 4 weeks.
Main Outcome Measures:
Both groups were tested 3 times, pretest and 2 and 4 weeks after training was initiated. Outcome measures included conscious appreciation of ankle kinesthesia, eversion and dorsiflexion isokinetic peak torque, and static and functional postural control.
Results revealed a significant Group × Test interaction only for inversion kinesthesia.
Four weeks of multiaxial coordination training did not significantly improve any of the dependent variables in healthy individuals. Further research should consider the effects of such a program on injured subjects.
Bradley T. Hayes, Rod A. Harter, Jeffrey J. Widrick, Daniel P. Williams, Mark A. Hoffman and Charlie A. Hicks-Little
Static stretching is commonly used during the treatment and rehabilitation of orthopedic injuries to increase joint range of motion (ROM) and muscle flexibility. Understanding the physiological adaptations that occur in the neuromuscular system as a result of long-term stretching may provide insight into the mechanisms responsible for changes in flexibility.
To examine possible neurological origins and adaptations in the Ia-reflex pathway that allow for increases in flexibility in ankle ROM, by evaluating the reduction in the synaptic transmission of Ia afferents to the motoneuron pool.
Repeated-measures, case-controlled study.
Sports medicine research laboratory.
40 healthy volunteers with no history of cognitive impairment, neurological impairment, or lower extremity surgery or injury within the previous 12 mo.
Presynaptic and postsynaptic mechanisms were evaluated with a chronic stretching protocol. Twenty subjects stretched 5 times a wk for 6 wk. All subjects were measured at baseline, 3 wk, and 6 wk.
Main Outcome Measures:
Ankle-dorsiflexion ROM, Hmax:Mmax, presynaptic inhibition, and disynaptic reciprocal inhibition.
Only ROM had a significant interaction between group and time, whereas the other dependent variables did not show significant differences. The experimental group had significantly improved ROM from baseline to 3 wk (mean 6.2 ± 0.9, P < .001), 3 wk to 6 wk (mean 5.0 ± 0.8, P < .001), and baseline to 6 wk (mean 11.2 ±0.9, P < .001).
Ankle dorsiflexion increased by 42.25% after 6 wk of static stretching, but no significant neurological changes resulted at any point of the study, contrasting current literature. Significant neuromuscular origins of adaptation do not exist in the Ia-reflex-pathway components after a long-term stretching program as currently understood. Thus, any increases in flexibility are the result of other factors, potentially mechanical changes or stretch tolerance.
Lee N. Burkett, Jack Chisum, Ralph Cook, Bob Norton, Bob Taylor, Keith Ruppert and Chris Wells
Numerous studies in the past 30 years have researched physiological adaptation to stress by wheelchair-bound subjects. Instrumentation necessary to produce this effect had to be designed and tested prior to obtaining valid data. This study had two main purposes: to design a wheelchair ergometer for physiological testing of spinal cord-injured subjects, and to demonstrate the validity of the maximal stress test when using the wheelchair ergometer. To test the validity of the wheelchair ergometer, 10 disabled subjects (9 paraplegic and 1 quadriplegic) participated in both a maximal field test (FT) and a maximal wheelchair ergometer test (WERG), with each subject serving as his or her own control. A randomly assigned counterbalanced design (5 subjects assigned to complete the FT first, with the second group of 5 subjects completing the WERG first) was used to reduce the learning effect in the study. The results of the t-tests indicated there was no significant difference between V̇O2 and V̇E, (STPD) averages for the WERG and FT for maximal effort with two-tailed significant levels of t = .9016 and t = .7294, respectively. The Pearson product moment correlation level was statistically significant at p < .0001, when the WERG V̇O2 was compared to the FT V̇O2 (r = .94), and was significant at p < .005 when the WERG V̇E was compared to the FT V̇E (r = .82).
MUST TAKE THIS QUIZ ONLINE. 1. In their CAT, Burton and Lauber explain that, during intense aerobic exercise, heat production can equate to a core body temperature (T c ) increase of 1°C every _________ minutes. a. 1–3 b. 3–5 c. 5–7 d. 7–9 2. Physiological adaptations to thermal strain include the
Andrew Cox, Marcie B. Fyock-Martin and Joel R. Martin
patients may benefit from alternative methods to decrease the impact of detraining and reduced activity on cardiovascular fitness. Aside from aerobic training, exposure to high altitudes has been shown to cause physiological adaptations leading to an increase in VO 2 max. 3 Since 1968 when the summer
Blair Mills, Brad Mayo, Francisco Tavares and Matthew Driller
. Furthermore, the effect size results in the current study are comparable with those reported in the previously mentioned studies. 1 , 2 It is possible that these acute responses, when implemented in a chronic setting, may lead to long-term physiological adaptations. Bohlen et al 5 assessed the benefits of
Andrew D. Nordin and Janet S. Dufek
injury mechanisms due to the rates of mechanical tissue breakdown exceeding the rates of physiological adaptation, thus leading to overuse injury, as outlined by James (2004) 17 in the variability-overuse injury hypothesis. In contrast to intra-individual variability, inter-individual variation often
Jill L. McNitt-Gray
weaknesses of the individual athlete. Understanding the biomechanics involved in this process provides important insights as to effective movement mechanics for task performance as well as positive physiological adaptations in response to training stimuli applied over time. Finding ways to support the
Amador García-Ramos, Alejandro Torrejón, Antonio J. Morales-Artacho, Alejandro Pérez-Castilla and Slobodan Jaric
Maximal sprints in the leg cycle ergometer exercise are commonly used in routine athletic testing as well as in studies investigating the physiological adaptations to strenuous exercise. 1 These tests provide valid measures of anaerobic performance, which is a determinant of success in short