Medicine and Science in Sports and Exercise最新文献

{"title":"Exercise, Sports Participation, and Quality of Life in Young Patients with Heritable Thoracic Aortic Disease.","authors":"Theodore J Millette, Randy K Ramcharitar, Oliver J Monfredi, Matthew J Thomas, Mark R Conaway, Peter N Dean","doi":"10.1249/MSS.0000000000003570","DOIUrl":"10.1249/MSS.0000000000003570","url":null,"abstract":"<p><strong>Introduction: </strong>Patients with heritable thoracic aortic disease (HTAD) are often restricted from sports and certain types of exercise. This study was designed to investigate the effect of lifetime exercise exposure and competitive sports participation on quality of life (QOL) in patients 15-35 yr old with syndromic (Marfan syndrome, Loeys-Dietz syndrome, and vascular Ehlers-Danlos syndrome) and nonsyndromic HTAD (nsHTAD).</p><p><strong>Methods: </strong>This cross-sectional study used questionnaires to assess lifetime exercise exposure and utilized the PedsQL QOL Inventory. We developed an exercise exposure score (EES) to quantify lifetime exercise exposure. Questionnaires were completed via telephone with complimentary medical record review.</p><p><strong>Results: </strong>Forty patients were enrolled. Mean age was 26 yr. The diagnosis was Marfan syndrome in 83%. Despite 88% of patients being restricted by their provider, 65% reported competitive sports participation and 93% reported recreational exercise. Participants with an EES greater than the median had significantly better total QOL scores compared with those below the median (78 vs 65, P = 0.03). There were significant positive correlations between current frequency of exercise and psychosocial QOL (slope = 3.9, 95% CI = 1.2-6.6, P = 0.005), physical QOL (slope = 8.1, 95% CI = 4.1-12, P < 0.001), and total QOL score (slope = 6.0, 95% CI = 3.1-9.0, P < 0.001). We found no difference in aortic size or need for surgical intervention between those above and below the median EES, or between those who did and did not participate in competitive sports.</p><p><strong>Conclusions: </strong>Despite exercise restrictions, young HTAD patients are physically active. Increased lifetime exercise and current physical activity levels were associated with improved QOL in HTAD patients.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"260-266"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mitochondrial Influence on Performance Fatigability: Considering Sex Variability.","authors":"Gaia Giuriato, Chiara Barbi, Fabio Giuseppe Laginestra, Mehran Emadi Andani, Thomas Favaretto, Camilla Martignon, Anna Pedrinolla, Gianluca Vernillo, Tatiana Moro, Martino Franchi, Maria Grazia Romanelli, Federico Schena, Massimo Venturelli","doi":"10.1249/MSS.0000000000003558","DOIUrl":"10.1249/MSS.0000000000003558","url":null,"abstract":"<p><strong>Objective: </strong>Existing literature indicates that females generally demonstrate higher fatigue resistance than males during isometric contractions. However, when it comes to single-limb dynamic exercises, the intricate interplay between performance fatigability (PF), cardiovascular responses, and muscle metabolism in relation to sex differences remains underexplored.</p><p><strong>Purpose: </strong>This study investigates how sex affects the relationship between muscle oxidative characteristics and the development of PF during dynamic single-leg exercise.</p><p><strong>Methods: </strong>Twenty-four young healthy participants (12 males vs 12 females) performed a constant-load single-leg knee extension task (85% peak power output; 60 rpm) to exhaustion (TTE). Neuromuscular assessments via transcranial magnetic and peripheral stimulations were conducted before and after exercise to evaluate central and peripheral factors of PF. Vastus lateralis muscle biopsies were obtained for mitochondrial respiration and immunohistochemistry analyses.</p><p><strong>Results: </strong>Participants performed similar total work (28 ± 7 vs 27 ± 14 kJ, P = 0.81) and TTE (371 ± 139 vs 377 ± 158 s, P = 0.98); after the TTE, females' maximal isometric voluntary contraction (MVIC: -36% ± 13% vs -24% ± 9%, P = 0.006) and resting twitch (RT; -65% ± 9% vs -40% ± 24%, P = 0.004) force declined less. No differences were observed in supraspinal neuromuscular factors ( P > 0.05). During exercise, the cardiovascular responses differed between sexes. Although fiber type composition was similar (type I: 47% ± 13% vs 56% ± 14%, P = 0.11), males had lower mitochondrial net oxidative capacity (61 ± 30 vs 89 ± 37, P = 0.049) and higher Complex II contribution to maximal respiration (CII; 59% ± 8% vs 48% ± 6%, P < 0.001), which correlated with the decline in MVIC ( r = -0.74, P < 0.001) and RT ( r = -0.60, P = 0.002).</p><p><strong>Conclusions: </strong>Females display greater resistance to PF during dynamic contractions, likely due to their superior mitochondrial efficiency and lower dependence on mitochondrial CII activity.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"376-389"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142133176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exercise and Heat Stress in Well-Healed Burn Survivors: Effects of Cooling Modalities on Thermal and Perceptual Responses.","authors":"Whitley C Atkins, Josh Foster, Zachary J McKenna, Caitlin P Jarrard, Joseph C Watso, Luke N Belval, Ollie Jay, Craig G Crandall","doi":"10.1249/MSS.0000000000003557","DOIUrl":"10.1249/MSS.0000000000003557","url":null,"abstract":"<p><strong>Purpose: </strong>Burn injuries that require grafting impair thermoregulation, which may dissuade individuals with such injuries from being physically active. We tested the hypothesis that cooling modalities attenuate core temperature elevations and perceptions of heat stress during physical activity in the heat among adults with well-healed burn injuries.</p><p><strong>Methods: </strong>Adults with no burn injuries (non-burned), 20%-40% body surface area burn injuries (moderate burn), and >40% body surface area burn injuries (large burn) performed 1 h of moderate-intensity exercise (2.5 ± 0.2 mph and 2% grade) on four different occasions in two environmental conditions (30°C and 39°C, 40% relative humidity). Within each environmental condition, we applied one of the following cooling modalities, random assigned, for each visit: no cooling (control), fan at 4 m·s -1 (fan), water spray every 5 min (water spray; scaled to burn area size), or a combination of water spray + fan.</p><p><strong>Results: </strong>In 30°C, perceptual strain index (PeSI) was reduced in the non-burned and moderate burn groups with water spray + fan, whereas PeSI was reduced with all cooling modalities in the large burn group. The cooling modalities did not affect core temperature responses. In the 39°C environment, water spray and water spray + fan attenuated the elevation in core temperature ( P ≤ 0.007) only in the large burn group. In the moderate burn group, PeSI was decreased with water spray + fan ( P = 0.017). In the large burn group, both water spray alone and water spray + fan ( P ≤ 0.041) lowered PeSI.</p><p><strong>Conclusions: </strong>For both environments across burn groups, the applied cooling modalities were generally more effective at reducing indices of perceptual strain relative to indices of thermal strain (e.g., core temperature).</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"365-375"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11729463/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142290796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Efficacy of Blood Flow Restriction Training to Improve Quadriceps Muscle Function after Anterior Cruciate Ligament Reconstruction.","authors":"Lauren N Erickson, Meredith K Owen, Kelsey R Casadonte, Tereza Janatova, Kathryn Lucas, Kylie Spencer, Benjamin D Brightwell, Megan C Graham, McKenzie S White, Nicholas T Thomas, Christine M Latham, Cale A Jacobs, Caitlin E Conley, Katherine L Thompson, Darren L Johnson, Peter A Hardy, Christopher S Fry, Brian Noehren","doi":"10.1249/MSS.0000000000003573","DOIUrl":"10.1249/MSS.0000000000003573","url":null,"abstract":"<p><strong>Background: </strong>Blood flow restriction training (BFRT) is a popular rehabilitation intervention after anterior cruciate ligament reconstruction (ACLR). However, there are a lack of clinical trials establishing the efficacy of using BFRT during rehabilitation to improve quadriceps muscle function.</p><p><strong>Purpose: </strong>The purpose of this study is to evaluate the efficacy of blood flow restriction training to improve quadriceps muscle strength, morphology, and physiology, and knee biomechanics in individuals after ACLR in a double-blind, randomized, placebo-controlled clinical trial (NCT03364647).</p><p><strong>Methods: </strong>Forty-eight athletes (20 females/28 males) were randomly assigned to low-load strength training with active BFRT or standard of care strength training with a sham unit. Treatment occurred for 1-month pre-surgery and 4 to 5 months post-surgery with both groups following the same standard rehabilitation protocol. Outcome variables were measured at baseline and 4 to 5 months post-surgery. Quadriceps muscle strength (isometric and isokinetic peak torque and rate of torque development) was measured on an isokinetic dynamometer. Quadriceps muscle morphology (physiological cross-sectional area, fibrosis) was determined using magnetic resonance imaging. Quadriceps muscle physiology (fiber type, fiber cross-sectional area, satellite cell abundance, collagen content, fibrogenic/adipogenic progenitor cells) was evaluated with muscle biopsies of the vastus lateralis. Knee extensor moment and knee flexion angle were measured via three-dimensional gait analysis. Change scores were calculated as: post-intervention - baseline. Two-sample t -tests were then used to assess between-group differences for each outcome variable.</p><p><strong>Results: </strong>No significant between-group differences were found for any outcome variable.</p><p><strong>Conclusions: </strong>The addition of BFRT to a rehabilitation program for athletes pre- and post-ACLR was no more effective than standard rehabilitation for improving quadriceps muscle function. Clinicians should consider the value of BFRT relative to the cost, time, and discomfort for patients in light of these results.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"227-237"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11729412/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Acute Dietary and Exercise Manipulation on Next-Day RMR Measurements and DXA Body Composition Estimates.","authors":"Megan A Kuikman, Ella Smith, Alannah K A McKay, Rachel McCormick, Kathryn E Ackerman, Rachel Harris, Kirsty J Elliott-Sale, Trent Stellingwerff, Louise M Burke","doi":"10.1249/MSS.0000000000003555","DOIUrl":"10.1249/MSS.0000000000003555","url":null,"abstract":"<p><strong>Purpose: </strong>The objective of this study is to investigate the effects of acute diet and exercise manipulation on resting metabolic rate (RMR) measurement variability and dual-energy x-ray absorptiometry (DXA) body composition estimates.</p><p><strong>Methods: </strong>Ten male and 10 female endurance athletes (12 cyclists, 5 triathletes, 4 runners) of tier 2 ( n = 18) to tier 3 ( n = 2) caliber underwent five conditions using a Latin square counterbalance design. For 24 h, athletes consumed a diet providing excessive energy availability (EA) (75 kcal⋅kg fat-free mass (FFM) -1 ) without exercise (GEA rest ), high-EA (45 kcal⋅kg FFM -1 ) without (HEA rest ) or with exercise (HEA ex ), or low-EA (15 kcal⋅kg FFM -1 ) without (LEA rest ) or with exercise (LEA ex ). Exercise involved two bouts of cycling (morning bout: 149 ± 34 min at 55% of maximal aerobic capacity (V̇O 2max ); afternoon bout: 60 min at 65% of V̇O 2max ) that resulted in a cumulative exercise energy expenditure of 30 kcal⋅kg FFM -1 . The following day, RMR and DXA measurements occurred after a 10-h fast and 12-h postexercise.</p><p><strong>Results: </strong>There were neither sex differences in relative RMR ( P = 0.158) nor effects of any of the five conditions on RMR ( P = 0.358). For both male and female athletes, FFM estimates were decreased following the LEA rest (-0.84 ± 0.66 kg; P = 0.001) and LEA ex (-0.65 ± 0.86 kg; P = 0.016) conditions compared with the GEA rest condition and following the LEA rest (-0.73 ± 0.51 kg; P = 0.001) and LEA ex (-0.54 ± 0.79 kg; P = 0.024) conditions compared with the HEA ex condition. There was no effect of condition on fat mass estimates ( P = 0.819).</p><p><strong>Conclusions: </strong>Acute periods of diet and exercise manipulation did not create artifacts in next-day RMR measurements. However, as changes in estimates of FFM were seen, diet and exercise should be controlled in the 24-h before DXA scans.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"285-295"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142290798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Exercise Intensity on Biathlon Standing Shooting Performance and Rifle Movement during Outdoor Roller Skiing.","authors":"Jørgen Danielsen, Harri Luchsinger, Anna Ravndal, Marko S Laaksonen, Øyvind Sandbakk, David McGhie","doi":"10.1249/MSS.0000000000003563","DOIUrl":"10.1249/MSS.0000000000003563","url":null,"abstract":"<p><strong>Purpose: </strong>The objective of this study is to investigate the effect of exercise intensity on standing shooting performance and related technical variables in elite biathletes performing roller skiing and live shooting outdoors.</p><p><strong>Methods: </strong>Nineteen male biathletes performed two 5-shot series in the following order of exercise intensity: rest, low (percentage of maximum heart rate, 73 ± 4; blood lactate, 1.5 ± 0.3 mmol·L -1 ), moderate (84 ± 3; 2.4 ± 0.6), \"race-pace\" (90 ± 2; 4.5 ± 0.8), and \"final-lap\" (i.e., near-maximal effort: 93 ± 3; 8.7 ± 1.4). Except for rest, each shooting series was preceded by 1-km roller ski skating on a competition track. Rifle movements and triggering were determined from marker-based motion capture and accelerometer data. The primary variables were shooting outcome (hit/miss) and distance from center (dC), determined from an electronic target, and barrel velocity. Mediation analyses for shooting outcome and dC were conducted with barrel velocity (mean over last 0.25 s before triggering) as mediator and intensity as predictor.</p><p><strong>Results: </strong>Exercise intensity increased the likelihood of miss at \"race\" (odds ratio (OR), 2.2; 95% CI, 1.0-4.7) and \"final-lap\" (OR, 2.8; 95% CI, 1.4-5.8) intensities compared with rest, with no meaningful differences between rest, low, and moderate intensities. Furthermore, intensity affected dC (~32 ± 15 mm at rest, low, and moderate, 36 ± 20 mm at \"race,\" and 40 ± 23 mm at \"final-lap\"; P < 0.001). Barrel velocity was a partial mediator of both shooting outcome and dC, explaining some, but not all, of the effect of intensity.</p><p><strong>Conclusions: </strong>Exercise intensity seems to have a clear negative effect on standing shooting performance in biathlon, which is partially explained by an increase in barrel velocity. Deteriorating effects were mainly seen at the two highest (race-like) intensities. Accordingly, for specificity reasons, more shooting practice should perhaps be performed at higher, competition-like exercise intensities than what is currently the norm.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"355-364"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interpreting the Projected Frontal Area in Front Crawl: Determining the Projected Frontal Area of Each Body Segment.","authors":"Sohei Washino, Akihiko Murai, Tomoya Kadi, Kenzo Narita, Hirotoshi Mankyu, Yasuhide Yoshitake","doi":"10.1249/MSS.0000000000003564","DOIUrl":"10.1249/MSS.0000000000003564","url":null,"abstract":"<p><strong>Purpose: </strong>This study aimed to provide evidence for the interpretation of the projected frontal area (PFA) during front crawl. To achieve this goal, we developed a method for calculating the PFA of each body segment using digital human technology and compared the pressure drag under two calculation conditions: a combination of the PFA with and without accounting for the horizontal velocity of each body segment.</p><p><strong>Methods: </strong>Twelve competitive male swimmers performed a 15-m front crawl at 1.20 m·s -1 . The three-dimensional positions of the reflective markers attached to the swimmer's body were recorded using an underwater motion-capture system. Based on the body shape of each swimmer obtained from the photogenic body scanner, individual digital human body models were created with the color of the model's vertices divided into eight body segments. The time series of the volumetric swimming motion was reconstructed using inverse kinematics. The PFA of each body segment was then calculated by the automatic processing of a series of parallel frontal images. The pressure drag index, defined as the value excluding the drag coefficient while simultaneously considering the PFA and the horizontal velocity, was calculated under two conditions: the static condition (accounting for only the PFA of each body segment) and the dynamic condition (accounting for the PFA and horizontal velocity of each body segment).</p><p><strong>Results: </strong>Notably, the pressure drag index was higher under the static condition than under the dynamic condition for the humerus, ulna, and hand segments ( P < 0.001).</p><p><strong>Conclusions: </strong>The results obtained using our methodology indicate that the PFA of the upper limb segments overestimates their contribution to pressure drag during front crawl under the static condition.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"390-399"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Obesity Promotes Marrow-Derived Myeloid Cell Accumulation While Exercise Reduces Proliferative Signaling in Colon Cancer.","authors":"James J Vanhie, Lisa Ek Orloff, Alice Tate, Cole Goode, Nicolas Collao, Anastasia Pisanko, Krista A Power, Michael DE Lisio","doi":"10.1249/MSS.0000000000003572","DOIUrl":"10.1249/MSS.0000000000003572","url":null,"abstract":"<p><strong>Purpose: </strong>Obesity increases colon cancer risk that has been previously linked to marrow-derived myeloid cells. We previously demonstrated that exercise training (EX) prevents colon cancer initiation, potentially through reduced myelopoiesis. However, it remains unknown whether early myeloid cell accumulation and inflammation in the colon precedes carcinogenesis with high-fat diet (HFD)-induced obesity, and if EX can attenuate these effects. We hypothesized that obesity would promote colon carcinogenesis that was preceded by myeloid cell accumulation and inflammation that would be attenuated by EX.</p><p><strong>Methods: </strong>C57BL/6 mice were randomized to a HFD or control (CON) diet for 8 weeks. The HFD mice switched to CON diet and all mice were given intraperitoneal injections of azoxymethane (AOM) to induce colon cancer and randomized into EX or sedentary (SED) conditions.</p><p><strong>Results: </strong>HFD mice developed more aberrant crypt foci (ACF), a marker for early carcinogenesis, compared with CON ( P < 0.01), and EX developed fewer ACF compared with SED ( P < 0.0001). Marrow-derived ( P < 0.001) CD206 + macrophages were elevated in HFD compared with CON at study week 16 ( P < 0.01). Marrow-derived CD206 - macrophages ( P < 0.05) and marrow-derived ( P < 0.05) CD206 + macrophages were more abundant in HFD compared with CON at study week 42. EX did not alter colon immune cell populations. β-catenin protein was higher in HFD compared with CON at study week 42 ( P < 0.05), and STAT3 protein content was lower at study week 28 with EX compared with SED ( P < 0.05).</p><p><strong>Conclusions: </strong>The results suggest that obesity promotes colon ACF formation, potentially through early inflammatory myeloid cell accumulation. Despite attenuating ACF, EX did not alter myeloid cell accumulation in the colon, suggesting that EX inhibits ACF formation through alternative mechanisms which may include reduced β-catenin and STAT3 signaling.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"317-326"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Setting Treadmill Intensity for Rat Aerobic Training Using Lactate and Gas Exchange Thresholds.","authors":"Koshiro Inoue, Hideaki Soya, Kei Murakumo, Yusuke Araki, Taichi Hiraga, Shingo Soya, Masahiro Okamoto","doi":"10.1249/MSS.0000000000003562","DOIUrl":"10.1249/MSS.0000000000003562","url":null,"abstract":"<p><strong>Purpose: </strong>To open up new horizons of translational research, we studied the lactate threshold (LT)-dependent physiological responses and adaptations to exercise in rats, highlighting the importance of intensity-specific studies for optimizing exercise prescriptions. LT is physiologically related to the noninvasive gas exchange threshold (GET), and both thresholds are moderate-heavy-intensity boundary indices in determining an effective intensity of aerobic training in humans. Although their practical utility is presumed to extend to rats, the actual existence of GET, the thresholds' relations to maximal oxygen consumption (V̇O 2max ), and whether aerobic adaptations by training differ around the LT intensity remain uncertain.</p><p><strong>Methods: </strong>This study sought to identify the GET using our previously established rat LT model by combining the use of a metabolic chamber and the V-slope method, and to confirm the thresholds' relations to V̇O 2max . We investigated changes in the thresholds and V̇O 2max following 6 wk of endurance training at below or above LT intensity.</p><p><strong>Results: </strong>GET and LT were significantly correlated and agreed with high precision, although with a fixed bias. Untrained rats exhibited GET and LT at 56% and 52% of their V̇O 2max , respectively. Endurance training at supra-, but not below-, the LT intensity significantly improved V̇O 2max and both thresholds; however, their %V̇O 2max remained unaltered.</p><p><strong>Conclusions: </strong>GET in rats is identifiable as a threshold associated with LT using the V-slope method. Furthermore, both thresholds can serve as moderate-heavy-intensity boundary indices for the aerobic training of rats. This study advances our understanding of exercise intensity regulation in rats, thereby contributing to the development of a more nuanced and effective model for exercise prescription, with implications for human health and fitness.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"434-446"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142349733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Walking Economy and Preferred Speed in Old and Very Old Men.","authors":"Eric Luneau, Vianney Rozand, Diana Rimaud, Clément Foschia, Guillaume Y Millet","doi":"10.1249/MSS.0000000000003565","DOIUrl":"10.1249/MSS.0000000000003565","url":null,"abstract":"<p><strong>Purpose: </strong>With aging, the decline in preferred walking speed (PWS), influenced by the increased energy cost of walking (CoW), is a key predictor of morbidity. However, the determinants associated with PWS and CoW remain poorly understood, especially after 80 yr old. The aim of the study was to characterize the amplitude and mechanisms of age-related decline in CoW and PWS in old (OM) and very old (VOM) men.</p><p><strong>Methods: </strong>Thirty-nine young men (YM; 22.1 ± 3.4 yr), 34 OM (71.7 ± 4.1 yr), and 23 VOM (85.8 ± 2.7 yr) performed aerobic, neuromuscular, and gait assessments. Net CoW was measured on a treadmill. Physical activity (PA) was evaluated by questionnaire and accelerometry.</p><p><strong>Results: </strong>Net CoW was 32% ( P < 0.001), 19% ( P < 0.01), and 26% ( P < 0.001) higher in VOM compared with OM for 1.11 m·s -1 , 1.67 m·s -1 , and PWS. Net CoW was also 27% ( P < 0.001), 26% ( P < 0.01), and 29% ( P < 0.001) higher in OM compared with YM at these speeds. Linear regression stratified by age showed that net CoW at PWS was associated with step frequency ( r = 0.79; P < 0.001) for OM and with both coefficient of variation of stride mean time ( r = 0.48; P < 0.05) and maximal strength of knee extensors ( r = -0.54; P < 0.05) for VOM. The same analysis revealed that PWS was correlated with net CoW ( r = -0.56; P < 0.05) and PA ( r = 0.47; P < 0.05) in VOM.</p><p><strong>Conclusions: </strong>The progressive increase in net CoW with age was associated with gait and neuromuscular impairments, particularly after the age of 80 yr. This increase in net CoW was related to a decrease in PWS in VOM, suggesting an adaptation of PWS to compensate for the increase in energy demand. Maintaining a high level of PA may potentially delay the age-related decline in PWS despite an age-related increase in net CoW.</p>","PeriodicalId":18426,"journal":{"name":"Medicine and Science in Sports and Exercise","volume":" ","pages":"400-412"},"PeriodicalIF":4.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142290801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}