The present study investigated the relative contribution of the cortical and spinal mechanisms for post-exercise excitability changes in human motoneurons. Seven healthy right-handed adults with no known neuromuscular disabilities performed an isometric voluntary wrist flexion at submaximum continuous exertion. After the subjects continued muscle contraction until volitional fatigue, the H-reflexes induced by an electric stimulation and motor evoked potentials (MEPs) induced by a transcranial magnetic stimulation (TMS) from a flexor carpi radialis (FCR) muscle were recorded 7 times every 20 s. The H-reflex was used to assess excitability changes at the spinal level, and the MEP was used to study excitability changes at the cortical level. H-reflexes showed a depression (30% of control value) soon after the cessation of wrist flexion and recovered with time thereafter. On the other hand, an early (short latency) MEP showed facilitation immediately after the cessation of wrist flexion (50% of control value) and thereafter decreased. A possible mechanism for the contradictory results of the 2 tests, in spite of focusing on the same motoneuron pool, might be the different test potential sizes between them. In addition, a late (long latency) MEP response appeared with increasing exercise. With regard to the occurrence of late MEP response, a central mechanism may be proposed to explain the origin—that is, neural pathways with a high threshold that do not participate under normal circumstances might respond to an emergency level of muscle exercise, probably reflecting central effects of fatigue.
Takashi Kato, Yusaku Takeda, Toshio Tsuji and Tatsuya Kasai
Stephan R. Fisher, Justin H. Rigby, Joni A. Mettler and Kevin W. McCurdy
– 1085 . PubMed ID: 25122099 doi:10.1097/PHM.0000000000000158 10.1097/PHM.0000000000000158 25122099 3. Hohenauer E , Taeymans J , Baeyens JP , Clarys P , Clijsen R . The effect of post-exercise cryotherapy on recovery characteristics: a systematic review and meta-analysis . PLoS ONE
Tyler T. Truxton and Kevin C. Miller
Exertional heat stroke (EHS) is a medical emergency which, if left untreated, can result in death. The standard of care for EHS patients includes confirmation of hyperthermia via rectal temperature (Trec) and then immediate cold-water immersion (CWI). While CWI is the fastest way to reduce Trec, it may be difficult to lower and maintain water bath temperature in the recommended ranges (1.7°C–15°C [35°F–59°F]) because of limited access to ice and/or the bath being exposed to high ambient temperatures for long periods of time. Determining if Trec cooling rates are acceptable (ie, >0.08°C/min) when significantly hyperthermic humans are immersed in temperate water (ie, ≥20°C [68°F]) has applications for how EHS patients are treated in the field.
Are Trec cooling rates acceptable (≥0.08°C/min) when significantly hyperthermic humans are immersed in temperate water?
Summary of Findings:
Trec cooling rates of hyperthermic humans immersed in temperate water (≥20°C [68°F]) ranged from 0.06°C/min to 0.19°C/min. The average Trec cooling rate for all examined studies was 0.11±0.06°C/min.
Clinical Bottom Line:
Temperature water immersion (TWI) provides acceptable (ie, >0.08°C/min) Trec cooling rates for hyperthermic humans post-exercise. However, CWI cooling rates are higher and should be used if feasible (eg, access to ice, shaded treatment areas).
Strength of Recommendation:
The majority of evidence (eg, Level 2 studies with PEDro scores ≥5) suggests TWI provides acceptable, though not ideal, Trec cooling. If possible, CWI should be used instead of TWI in EHS scenarios.
Lee N. Burkett, Jack Chisum, Jack Pierce, Kent Pomeroy, Jim Fisher and Margie Martin
Twenty spinal-cord-injured subjects (4 quadriplegics and 16 paraplegics) were maximally stress tested on the Arizona State University wheelchair ergometer. Physiological data for each individual were collected as follows: (a) blood flow in the left leg by a photoelectric plethysmograph before exercise, during exercise, and postexercise, and (b) blood lactates before exercise and post-exercise. Eleven subjects had increased leg blood flow and vasodilation during exercise, but vasoconstriction postexercise. The lactate readings, in comparison to able-bodied individuals, were higher at rest but lower at maximal exercise.
Douglas A. Pizac, Charles B. Swanik, Joseph J. Glutting and Thomas W. Kaminski
treatments pre- and post-exercise are highlighted in Table 3 . After controlling for order of treatment and the prepractice measurements, no significant differences were found in the single-leg firm or sum of the 3 stances of the error scores (Table 4 ). Error scores for the double-leg firm stance and the
Kayla E. Boehm and Kevin C. Miller
reached 37.5°C. – Subjects were immersed in a recumbent position (head and chest were not fully immersed). Results T rec post exercise: female = 41.9°C; male = 41.6°C (0.6°C). Immersion duration: female = 11 min; male = 17 (8) min. T rec cooling rate: female = 0.27°C/min; male = 0.20 (0.07)°C/min. T rec
Dawn M. Emerson, Toni M. Torres-McGehee, Susan W. Yeargin, Kyle Dolan and Kelcey K. deWeber
:10.1123/ijatt.2018-0133 17. Maughan RJ , Leiper JB . Sodium intake and post-exercise rehydration in man . Eur J Appl Physiol . 1995 ; 71 : 311 – 319 . doi:10.1007/BF00240410 10.1007/BF00240410 18. Shirreffs SM , Maughan RJ . Restoration of fluid balance after exercise
Jeffrey R. Doeringer, Megan Colas, Corey Peacock and Dustin R. Gatens
-body cryotherapy in athletes . Sports Med . 2010 ; 40 ( 6 ): 509 – 517 . PubMed doi:10.2165/11531940-000000000-00000 10.2165/11531940-000000000-00000 20524715 2. Hohenauer E , Taeymans J , Baeyens JP , Clarys P , Clijsen R . The effect of post-exercise cryotherapy on recovery characteristics: a
Scott W. Cheatham
. • Performance enhancement • Injury prevention • Treatment of injury • Pre-exercise warm-up and post-exercise treatment 14) What is the common time range you prescribe for a pre or post-exercise session per muscle group? • 30 seconds or less • 30 seconds to 1
Jesús Seco-Calvo, Juan Mielgo-Ayuso, César Calvo-Lobo and Alfredo Córdova
. 16937951 10.2165/00007256-200636090-00003 9. Vanderlei FM , de Albuquerque MC , de Almeida AC , Machado AF , Netto J , Pastre CM . Post-exercise recovery of biological, clinical and metabolic variables after different temperatures and durations of cold water immersion: a randomized