These references summarize the research on the effects of massage on blood flow and recovery from exercise and provide research on lactic acid physiology to dispel the myths. A Moraska author 2005-Sep text continuing periodical academic journal 0022-4707 2005-Sep 45 3 370 380 The science of sports massage is of interest to many populations including athletes, athletic trainers, coaches, as well as sports physiologists. While evidence to support or refute the effects of massage on sports performance is insufficient to make definitive statements, new reports and trends within data help formulate an understanding of sports massage. This article will review sports massage research on topics including lactate clearance, delayed onset of muscle soreness (DOMS), muscle fatigue, the psychological effect of massage, and injury prevention and treatment. Articles referenced in Medline, Cochrane Database, the authors library, and references from articles are included in this review. Most studies contain methodological limitations including inadequate therapist training, insufficient duration of treatment, few subjects, or over or under working of muscles that limit a practical conclusion. Muscle soreness associated with DOMS is reduced with massage, although whether force recovers more quickly is still unclear. The research literature to date is insufficient to conclude whether massage facilitates recovery from a fatiguing effort. Both tissue healing and a psychological effect of massage are areas that may prove promising with further research. Results from published literature support a positive trend for massage to benefit athletic recovery and performance; a need for further research into sports massage, especially well-designed studies utilizing therapists specifically trained to administer this type of therapy, is warranted. Moraska2005 Zainal Zainuddin author Mike Newton author Paul Sacco author Kazunori Nosaka author 2005-Jul text continuing periodical academic journal 1062-6050 2005-Jul 40 3 174 180 Context: Delayed-onset muscle soreness (DOMS) describes muscle pain and tenderness that typically develop several hours postexercise and consist of predominantly eccentric muscle actions, especially if the exercise is unfamiliar. Although DOMS is likely a symptom of eccentric-exercise-induced muscle damage, it does not necessarily reflect muscle damage. Some prophylactic or therapeutic modalities may be effective only for alleviating DOMS, whereas others may enhance recovery of muscle function without affecting DOMS.Objective: To test the hypothesis that massage applied after eccentric exercise would effectively alleviate DOMS without affecting muscle function.Design: We used an arm-to-arm comparison model with 2 independent variables (control and massage) and 6 dependent variables (maximal isometric and isokinetic voluntary strength, range of motion, upper arm circumference, plasma creatine kinase activity, and muscle soreness). A 2-way repeated-measures analysis of variance and paired t tests were used to examine differences in changes of the dependent variable over time (before, immediately and 30 minutes after exercise, and 1, 2, 3, 4, 7, 10, and 14 days postexercise) between control and massage conditions.Setting: University laboratory.Patients or Other Participants: Ten healthy subjects (5 men and 5 women) with no history of upper arm injury and no experience in resistance training.Intervention(s): Subjects performed 10 sets of 6 maximal isokinetic (90 degrees .s) eccentric actions of the elbow flexors with each arm on a dynamometer, separated by 2 weeks. One arm received 10 minutes of massage 3 hours after eccentric exercise; the contralateral arm received no treatment.Main Outcome Measure(s): Maximal voluntary isometric and isokinetic elbow flexor strength, range of motion, upper arm circumference, plasma creatine kinase activity, and muscle soreness.Results: Delayed-onset muscle soreness was significantly less for the massage condition for peak soreness in extending the elbow joint and palpating the brachioradialis muscle (P < .05). Soreness while flexing the elbow joint (P = .07) and palpating the brachialis muscle (P = .06) was also less with massage. Massage treatment had significant effects on plasma creatine kinase activity, with a significantly lower peak value at 4 days postexercise (P < .05), and upper arm circumference, with a significantly smaller increase than the control at 3 and 4 days postexercise (P < .05). However, no significant effects of massage on recovery of muscle strength and ROM were evident.Conclusions: Massage was effective in alleviating DOMS by approximately 30% and reducing swelling, but it had no effects on muscle function. Zainuddin2005 Pornratshanee Weerapong author Patria A Hume author Gregory S Kolt author 2005 text continuing periodical academic journal 0112-1642 2005 35 3 235 256 Many coaches, athletes and sports medicine personnel hold the belief, based on observations and experiences, that massage can provide several benefits to the body such as increased blood flow, reduced muscle tension and neurological excitability, and an increased sense of well-being. Massage can produce mechanical pressure, which is expected to increase muscle compliance resulting in increased range of joint motion, decreased passive stiffness and decreased active stiffness (biomechanical mechanisms). Mechanical pressure might help to increase blood flow by increasing the arteriolar pressure, as well as increasing muscle temperature from rubbing. Depending on the massage technique, mechanical pressure on the muscle is expected to increase or decrease neural excitability as measured by the Hoffman reflex (neurological mechanisms). Changes in parasympathetic activity (as measured by heart rate, blood pressure and heart rate variability) and hormonal levels (as measured by cortisol levels) following massage result in a relaxation response (physiological mechanisms). A reduction in anxiety and an improvement in mood state also cause relaxation (psychological mechanisms) after massage. Therefore, these benefits of massage are expected to help athletes by enhancing performance and reducing injury risk. However, limited research has investigated the effects of pre-exercise massage on performance and injury prevention. Massage between events is widely investigated because it is believed that massage might help to enhance recovery and prepare athletes for the next event. Unfortunately, very little scientific data has supported this claim. The majority of research on psychological effects of massage has concluded that massage produces positive effects on recovery (psychological mechanisms). Post-exercise massage has been shown to reduce the severity of muscle soreness but massage has no effects on muscle functional loss. Notwithstanding the belief that massage has benefits for athletes, the effects of different types of massage (e.g. petrissage, effleurage, friction) or the appropriate timing of massage (pre-exercise vs post-exercise) on performance, recovery from injury, or as an injury prevention method are not clear. Explanations are lacking, as the mechanisms of each massage technique have not been widely investigated. Therefore, this article discusses the possible mechanisms of massage and provides a discussion of the limited evidence of massage on performance, recovery and muscle injury prevention. The limitations of previous research are described and further research is recommended. Weerapong2005 Tessa Hinds author Islay McEwan author Jill Perkes author Ellen Dawson author Derek Ball author Keith George author 2004-Aug text continuing periodical academic journal 0195-9131 2004-Aug 36 8 1308 1313 PURPOSE: At present, there is little scientific evidence that postexercise manual massage has any effect on the factors associated with the recovery process. The purpose of this study was to compare the effects of massage against a resting control condition upon femoral artery blood flow (FABF), skin blood flow (SKBF), skin (SKT), and muscle (MT) temperature after dynamic quadriceps exercise. METHODS: Thirteen male volunteers participated in 3 x 2-min bouts of concentric quadriceps exercise followed by 2 x 6-min bouts of deep effleurage and pétrissage massage or a control (rest) period of similar duration in a counterbalanced fashion. Measures of FABF, SKBF, SKT, MT, blood lactate concentration (BLa), heart rate (HR), and blood pressure (BP) were taken at baseline, immediately after exercise, as well as at the midpoint and end of the massage/rest periods. Data were analyzed by two-way ANOVA. RESULTS: Significant main effects were found for all variables over time due to effects of exercise. Massage to the quadriceps did not significantly elevate FABF (end-massage 760 +/- 256 vs end-control 733 +/- 161 mL x min(-1)), MT, BL, HR, and BP over control values (P < 0.05). SKBF (end-massage 150 +/- 49 vs end control 6 +/- 4 au) SKT (end-massage 32.2 +/- 0.9 vs end-control 31.1 +/- 1.3degreesC) were elevated after the application of massage compared with the control trial (P < 0.05). CONCLUSION: From these data it is proposed that without an increase in arterial blood flow, any increase in SKBF is potentially diverting flow away from recovering muscle. Such a response would question the efficacy of massage as an aid to recovery in postexercise settings. Hinds2004 Hidetoshi Mori author Hideo Ohsawa author Tim Hideaki Tanaka author Eiichi Taniwaki author Gerry Leisman author Kazushi Nishijo author 2004-May-28 text continuing periodical academic journal 1234-1010 2004-May-28 10 5 CR173 CR178 BACKGROUND: This study attempted to investigate the influence of massage on the skin and the intramuscular circulatory changes associated with localized muscle fatigue. MATERIAL/METHODS: Twenty-nine healthy male subjects participated in two experimental sessions (massage and rest conditions). Subjects lay prone on the table and were instructed to extend their trunks until the inferior portion of their rib cage no longer rested on the table. Subjects held this position for 90 seconds (Load I). Subjects then either received massage on the lumbar region or rested for 5 minutes, then repeated the same load (Load II). Skin blood flow (SBF), muscle blood volume (MBV), skin temperature (ST), and subjects' subjective feelings of fatigue were evaluated using Visual Analogue Scale (VAS). RESULTS: An increase of MBV between pre- and post-load II periods was higher after massage than after rest (p<0.05). An increase of SBF at pre- and post-load II was observed only under massage condition. An increase of SBF between post-load I and pre-load II periods was higher after massage than after rest (p<0.05). An increase of ST between post-load I and post-load II periods was greater after massage than after rest (p<0.05). The VAS score was lower with massage than with rest in the post-treatment period (p<0.01). CONCLUSIONS: A significant difference was observed between massage and rest condition on VAS for muscle fatigue. Lumbar massage administration also appeared to have some effect on increasing skin temperature and enhancement of blood flow in local regions. Mori2004 A Robertson author J M Watt author S D R Galloway author 2004-Apr text continuing periodical academic journal 0306-3674 2004-Apr 38 2 173 176 BACKGROUND: The effect of massage on recovery from high intensity exercise is debatable. Many studies on massage suffer from methodological flaws such as poor standardisation of previous exercise, lack of dietary control, and inappropriate massage duration. OBJECTIVE: To examine the effects of leg massage compared with passive recovery on lactate clearance, muscular power output, and fatigue characteristics after repeated high intensity cycling exercise, with the conditions before the intervention controlled and standardised. METHODS: Nine male games players participated. They attended the laboratory on two occasions one week apart and at the same time of day. Dietary intake and activity were replicated for the two preceding days on each occasion. After baseline measurement of heart rate and blood lactate concentration, subjects performed a standardised warm up on the cycle ergometer. This was followed by six standardised 30 second high intensity exercise bouts, interspersed with 30 seconds of active recovery. After five minutes of active recovery and either 20 minutes of leg massage or supine passive rest, subjects performed a second standardised warm up and a 30 second Wingate test. Capillary blood samples were drawn at intervals, and heart rate, peak power, mean power, and fatigue index were recorded. RESULTS: There were no significant differences in mean power during the initial high intensity exercise bouts (p = 0.92). No main effect of massage was observed on blood lactate concentration between trials (p = 0.82) or heart rate (p = 0.81). There was no difference in the maximum power (p = 0.75) or mean power (p = 0.66) in the subsequent Wingate test, but a significantly lower fatigue index was observed in the massage trial (p = 0.04; mean (SD) fatigue index 30.2 (4.1)% v 34.2 (3.3)%). CONCLUSIONS: No measurable physiological effects of leg massage compared with passive recovery were observed on recovery from high intensity exercise, but the subsequent effect on fatigue index warrants further investigation. Robertson2004 B Drust author G Atkinson author W Gregson author D French author D Binningsley author 2003-Aug text continuing periodical academic journal 0172-4622 2003-Aug 24 6 395 399 The aim of the current investigation was to evaluate the effect of different durations of massage, and ultrasound treatment, on the temperature of the vastus lateralis muscle in males. Deep effleurage massage of the vastus lateralis was performed on seven healthy males (mean +/- SD; age; 28 +/- 4 years, height 1.84 +/- 0.05 m, body mass 85.7 +/- 12 kg) for 5, 10 and 15 min periods. A 5-min period of ultrasound at 45 KHz was also completed by all subjects. Intra muscular temperature (at 1.5, 2.5 and 3.5 cm) and thigh skin temperature were assessed pre and post treatment. Heart rate was monitored continuously throughout all conditions. Pre treatment intra muscular temperature increased as depth of measurement increased (p = 0.00002). Changes in muscle temperature at 1.5 and 2.5 cm were significantly greater following massage than ultrasound (p < 0.002). No significant differences between massage treatments and ultrasound were noted when intra muscular temperature was measured at 3.5 cm (p > 0.05). Massage also significantly increased both heart rate and thigh skin temperature compared to ultrasound (p < 0.005). Increases in intra muscular temperature, heart rate and thigh skin temperature were the same irrespective of massage duration. These data suggest that massage and ultrasound have only limited effects on deep muscle temperature. As a result such approaches may not be suitable as a preparation strategy for exercise.\ Drust2003 10.1055/s-2003-41182 J Monedero author B Donne author 2000-Nov text continuing periodical academic journal 0172-4622 2000-Nov 21 8 593 597 The recovery process in sport plays an essential role in determining subsequent athletic performance. This study investigated the effectiveness of different recovery interventions after maximal exercise. Eighteen trained male cyclists initially undertook an incremental test to determine maximal oxygen consumption. The four recovery interventions tested were: passive, active (50% maximal oxygen uptake), massage, and combined (involving active and massage components). All test sessions were separated by 2 to 3 days. During intervention trials subjects performed two simulated 5 km maximal effort cycling tests (T1 and T2) separated by a 20 min recovery. Performance time for the tests (t1, t2); blood lactate (BLa) during T1, T2, and every 3 min during recovery; and heart rate (HR) during the recovery intervention and T2 were recorded. Combined recovery was found to be better than passive (P<0.01) and either active or massage (P<0.05) in maintenance of performance time during T2. Active recovery was the most effective intervention for removing BLa at minutes 9 and 12, BLa removal during combined recovery was significantly better than passive at minute 3, and significantly better than passive, active, and massage at minute 15. In conclusion, combined recovery was the most efficient intervention for maintaining maximal performance time during T2, and active recovery was the best intervention for removing BLa. Monedero2000 B Hemmings author M Smith author J Graydon author R Dyson author 2000-Apr text continuing periodical academic journal 0306-3674 2000-Apr 34 2 109 109 BACKGROUND: Despite massage being widely used by athletes, little scientific evidence exists to confirm the efficacy of massage for promoting both physiological and psychological recovery after exercise and massage effects on performance. AIM: To investigate the effect of massage on perceived recovery and blood lactate removal, and also to examine massage effects on repeated boxing performance. METHODS: Eight amateur boxers completed two performances on a boxing ergometer on two occasions in a counterbalanced design. Boxers initially completed performance 1, after which they received a massage or passive rest intervention. Each boxer then gave perceived recovery ratings before completing a second performance, which was a repeated simulation of the first. Heart rates and blood lactate and glucose levels were also assessed before, during, and after all performances. RESULTS: A repeated measures analysis of variance showed no significant group differences for either performance, although a main effect was found showing a decrement in punching force from performance 1 to performance 2 (p<0.05). A Wilcoxon matched pairs test showed that the massage intervention significantly increased perceptions of recovery (p<0.01) compared with the passive rest intervention. A doubly multivariate multiple analysis of variance showed no differences in blood lactate or glucose following massage or passive rest interventions, although the blood lactate concentration after the second performance was significantly higher following massage (p<0.05). CONCLUSIONS: These findings provide some support for the psychological benefits of massage, but raise questions about the benefit of massage for physiological restoration and repeated sports performance. Hemmings2000 P M Tiidus author 1999-Jun text continuing periodical academic journal 1066-7814 1999-Jun 24 3 267 278 Although both massage and ultrasound treatment are used in clinical settings to enhance muscle functional recovery following exercise-induced muscle damage, there is a paucity of experimental evidence for their efficacy. Theoretically both massage and ultrasound could affect some physiological factors associated with enhancement of postexercise muscle recovery. However, the actual physiological mechanisms by which massage or ultrasound could influence postexercise muscle damage and repair are unknown. Most experimental evidence suggests that massage has little influence on muscle blood flow, clearance of "noxious" substances, recovery of postexercise muscle strength, or delayed soreness sensation. However, more data is needed before conclusions can be drawn as to the ability of massage to influence postexercise inflammatory response or various other physiological changes that characterize exercise-induced muscle damage and repair. There is even less information on the ability of ultrasound to influence physiological or functional factors associated with postexercise muscle damage. The few experiments that have been done tend to be contradictory and have yet to consider the range of ultrasound treatment parameters for therapeutic effectiveness in treating postexercise damage and influencing repair processes. Much more research is needed to determine whether either treatment modality can have any therapeutic effect on exercise-induced muscle damage and recovery of postexercise muscle function. Tiidus1999 E Ernst author 1998-Sep text continuing periodical academic journal 0306-3674 1998-Sep 32 3 212 214 BACKGROUND: Delayed onset muscle soreness (DOMS) is a frequent problem after unaccustomed exercise. No universally accepted treatment exists. Massage therapy is often recommended for this condition but uncertainty exists about its effectiveness. AIM: To determine whether post-exercise massage alleviates the symptoms of DOMS after a bout of strenuous exercise. METHOD: Various computerised literature searches were carried out and located seven controlled trials. RESULTS: Most of the trials were burdened with serious methodological flaws, and their results are far from uniform. However, most suggest that post-exercise massage may alleviate symptoms of DOMS. CONCLUSIONS: Massage therapy may be a promising treatment for DOMS. Definitive studies are warranted. Ernst1998 J K Shoemaker author P M Tiidus author R Mader author 1997-May text continuing periodical academic journal 0195-9131 1997-May 29 5 610 614 The ability of manual massage to alter muscle blood flow through three types of massage treatments in a small (forearm) and a large (quadriceps) muscle mass was tested in 10 healthy individuals. A certified massage therapist administered effleurage, petrissage, and tapotement treatments to the forearm flexors (small muscle mass) and quadriceps (large muscle mass) muscle groups in a counterbalanced manner. Limb blood flow was determined from mean blood velocity (MBV) (pulsed Doppler) and vessel diameter (echo Doppler). MBV values were obtained from the continuous data sets prior to treatment, and at 5, 10, and 20 s and 5 min following the onset of massage. Arterial diameters were measured immediately prior to and following the massage treatments; these values were not different and were averaged for the blood flow calculations. The MBV (e.g., 5.77 +/- 0.4 and 9.73 +/- 0.7 cm.s-1) and blood flows (39.1 +/- 6.4 and 371 +/- 30 ml.min-1) for brachial and femoral arteries, respectively, were not altered by any of the massage treatments in either the forearm or quadriceps muscle groups (P > 0.05). Mild voluntary handgrip (approximately 35% maximal voluntary isometric contraction) and knee extension (15 cm) contractions resulted in peak blood velocities (15.2 +/- 1.2 and 28.1 +/- 3.1 cm.s-1) and blood flow (126 +/- 19 and 1087 +/- 144 ml.min-1) for brachial and femoral arteries, respectively, which were significantly elevated from rest (P < 0.05). The results indicate that manual massage does not elevate muscle blood flow irrespective of massage type or the muscle mass receiving the treatment. Further, the results indicate that if an elevated muscle blood flow is the desired therapeutic effect, then light exercise would be beneficial whereas massage would not. Shoemaker1997 P M Tiidus author 1997-Feb text continuing periodical academic journal 0190-6011 1997-Feb 25 2 107 112 There is currently little scientific evidence that manual massage has any significant impact on the short- or long-term recovery of muscle function following exercise or on the physiological factors associated with the recovery process. In addition, delayed onset muscle soreness may not be affected by massage. Light exercise of the affected muscles is probably more effective than massage in improving muscle blood flow (thereby possibly enhancing healing) and temporarily reducing delayed onset muscle soreness. This paper reviews current scientific evidence on the use of manual massage to affect: 1) muscle damage caused by eccentric muscle action; 2) retention and recovery of muscle strength and performance following "eccentric-mechanical" muscle damage; 3) reduction of delayed onset muscle soreness following "eccentric-mechanical" muscle damage; and 4) recovery of muscle strength and performance following anaerobic exercise. Because manual massage does not appear to have a demonstrated effect on the above, its use in athletic settings for these purposes should be questioned. Tiidus1997 S Gupta author A Goswami author A K Sadhukhan author D N Mathur author 1996-Feb text continuing periodical academic journal 0172-4622 1996-Feb 17 2 106 110 This investigation highlights the comparison of blood lactate removal during the period of recovery in which the subjects were required to sit down as a passive rest period, followed by active recovery at 30% VO(2)max and short term body massage, as the three modes of recovery used. Ten male athletes participated in the study. Exercise was performed on a bicycle ergometer with loads at 150% VO(2)max, each session lasting 1 min, interspaced with 15 sec rest periods, until exhaustion. Blood lactate concentration was recorded at recovery periods of 0,3, 5, 10, 20, 30, and 40 min, while VO(2), VCO(2) and heart rate were recorded every 30 sec for 30 min. The highest mean lactate value was found after 3 min of recovery irrespective of the type of modality applied. Significantly lower half life of lactate was observed during active recovery (15.7 +/- 2.5 min) period, while short term massage as a means of recovery required 21.8 +/- 3.5 min and did not show any significant difference from a passive type of sitting recovery period of 21.5 +/- 2.8 min. Analysis of lactate values indicated no remarkable difference between massage and a passive type of sitting recovery period. It was observed that in short term massage recovery, more oxygen was consumed as compared to a passive type of sitting recovery. It is concluded from the study that the short term body massage is ineffective in enhancing the lactate removal and that an active type of recovery is the best modality for enhancing lactate removal after exercise. Gupta1996 P M Tiidus author J K Shoemaker author 1995-Oct text continuing periodical academic journal 0172-4622 1995-Oct 16 7 478 483 Manual massage is commonly assumed to enhance long term muscle recovery from intense exercise, partly due to its ability to speed healing via enhanced muscle blood flow. We tested these assumptions by daily (for four days) massaging the quadriceps muscles of one leg on subjects who had previously completed an intense bout of eccentric quadriceps work with both legs. Immediate post-exercise isometric and dynamic quadriceps peak torque measures had declined to approximately 60-70% of pre-exercise values in both legs. Peak torques for both the massage and control leg tended to slowly return toward pre-exercise values through the subsequent four days (96 hrs). There was no significant difference between the isometric and dynamic peak torques between massage and control legs up to 96 hours post-exercise. Leg blood flow was estimated by determining femoral artery and vein mean blood velocities via pulsed Doppler ultrasound velocimetry. Massage of the quadriceps muscles did not significantly elevate arterial or venous mean blood velocity above resting levels, while light quadriceps muscle contractions did. The perceived level of delayed onset muscle soreness tended to be reduced in the massaged leg 48-96 hours post-exercise. It was concluded that massage was not an effective treatment modality for enhancing long term restoration of post-exercise muscle strength and its use for this purpose in athletic settings should be questioned. Tiidus1995 P J Arkko author A J Pakarinen author O Kari-Koskinen author 1983-Nov text continuing periodical academic journal 0172-4622 1983-Nov 4 4 265 267 The effects of a 1-h whole body massage on blood parameters were studied in nine healthy male volunteers. The venous blood samples were drawn just before treatment, immediately after, and after 2, 24, and 48 h. The parameters measured were blood leukocyte and erythrocyte counts, hemoglobin concentration, hematocrit, red cell indices, the activities of serum creatine kinase, lactate dehydrogenase and their isoenzymes, and the concentrations of serum sodium, potassium, total protein, haptoglobin, growth hormone, prolactin, cortisol, and plasma corticotropin. Decreases in serum haptoglobin concentrations suggested slight hemolysis. The rises in the activities of creatine kinase, lactate dehydrogenase, and its isoenzymes LDH4 and LDH5 and in the concentrations of serum potassium are indicative of increased permeability of the muscle cells. No statistically significant changes were seen for the other parameters. There were large individual variabilities in the hormone concentrations after massage, but some trends could be seen. Arkko1983 Enhanced: Lactic Acid—The Latest Performance-Enhancing Drug David Allen author Håkan Westerblad author 2004-08-20 text continuing periodical academic journal 10.1126/science.1103078 Allen2004 http://www.sciencemag.org 2004-8-20 305 5687 1112 1113 a new paradigm for the third millennium L B Gladden author 2004-07-183 text continuing periodical academic journal For much of the 20th century, lactate was largely considered a dead-end waste product of glycolysis due to hypoxia, the primary cause of the O2 debt following exercise, a major cause of muscle fatigue, and a key factor in acidosis-induced tissue damage. Since the 1970s, a 'lactate revolution' has occurred. At present, we are in the midst of a lactate shuttle era; the lactate paradigm has shifted. It now appears that increased lactate production and concentration as a result of anoxia or dysoxia are often the exception rather than the rule. Lactic acidosis is being re-evaluated as a factor in muscle fatigue. Lactate is an important intermediate in the process of wound repair and regeneration. The origin of elevated [lactate] in injury and sepsis is being re-investigated. There is essentially unanimous experimental support for a cell-to-cell lactate shuttle, along with mounting evidence for astrocyte-neuron, lactate-alanine, peroxisomal and spermatogenic lactate shuttles. The bulk of the evidence suggests that lactate is an important intermediary in numerous metabolic processes, a particularly mobile fuel for aerobic metabolism, and perhaps a mediator of redox state among various compartments both within and between cells. Lactate can no longer be considered the usual suspect for metabolic 'crimes', but is instead a central player in cellular, regional and whole body metabolism. Overall, the cell-to-cell lactate shuttle has expanded far beyond its initial conception as an explanation for lactate metabolism during muscle contractions and exercise to now subsume all of the other shuttles as a grand description of the role(s) of lactate in numerous metabolic processes and pathways. 10.1113/jphysiol.2003.058701 Gladden2004 http://www.blackwell-synergy.com/doi/abs/10.1113/jphysiol.2003.058701 2004-07-183 558 1 5 30 Lactic acid accumulation is an advantage/disadvantage during muscle activity Graham D Lamb author D George Stephenson author Jens Bangsbo author Carsten Juel author 2006-04-01 text continuing periodical academic journal 10.1152/japplphysiol.00023.2006 Lamb2006 http://jap.physiology.org 2006-4-1 100 4 1410 1412 Michael Ivan Lindinger author George A Brooks author Gregory C Henderson author Takeshi Hashimoto author Tamara Mau author Jill A Fattor author Michael A Horning author Raja Hussien author Hyung-Sook Cho author Nastaran Faghihnia author Zinta Zarins author L Bruce Gladden author Michael C Hogan author John Vissing author Russell Tupling author 2006-06-01 text continuing periodical academic journal 10.1152/japplphysiol.00213.2006 Lindinger2006 http://jap.physiology.org 2006-6-1 100 6 2100 2102 Thomas H Pedersen author Ole B Nielsen author Graham D Lamb author D George Stephenson author 2004-08-20 text continuing periodical academic journal Intracellular acidification of skeletal muscles is commonly thought to contribute to muscle fatigue. However, intracellular acidosis also acts to preserve muscle excitability when muscles become depolarized, which occurs with working muscles. Here, we show that this process may be mediated by decreased chloride permeability, which enables action potentials to still be propagated along the internal network of tubules in a muscle fiber (the T system) despite muscle depolarization. These results implicate chloride ion channels in muscle function and emphasize that intracellular acidosis of muscle has protective effects during muscle fatigue. 10.1126/science.1101141 Pedersen2004 http://www.sciencemag.org/cgi/content/abstract/305/5687/1144 2004-8-20 305 5687 1144 1147 Lactic Acid or Inorganic Phosphate the Major Cause? Hakan Westerblad author David G Allen author Jan Lannergren author 2002-02-01 text continuing periodical academic journal Intracellular acidosis due mainly to lactic acid accumulation has been regarded as the most important cause of skeletal muscle fatigue. Recent studies on mammalian muscle, however, show little direct effect of acidosis on muscle function at physiological temperatures. Instead, inorganic phosphate, which increases during fatigue due to breakdown of creatine phosphate, appears to be a major cause of muscle fatigue. Westerblad2002 http://physiologyonline.physiology.org/cgi/content/abstract/17/1/17 2002-2-1 17 1 17 21