https://journals.lww.com/acsm-msse/pages/currenttoc.aspx en-us Thu, 07 Aug 2025 08:56:50 -0500 Wolters Kluwer Health RSS Generator https://images.journals.lww.com/acsm-msse/XLargeThumb.00005768-202508000-00000.CV.jpeg https://journals.lww.com/acsm-msse/pages/currenttoc.aspx https://journals.lww.com/acsm-msse/fulltext/2025/08000/physical_activity_and_sedentary_behavior_differ_by.1.aspx Introduction/Purpose Females have lower physical activity (PA) levels and inferior outcomes compared with males following formal rehabilitation after anterior cruciate ligament (ACL) reconstruction. This observational study aimed to determine if PA levels and sedentary behavior change and vary by sex during the time before and 6 months after ACL reconstruction. Methods PA and sedentary behavior were measured in an observational cohort of 30 participants (19.6 ± 4.9 yr old, 66.7% female) using a three-axis accelerometer before (preoperative) and at 2, 4, and 6 months after ACL reconstruction. Daily steps, daily minutes of moderate to vigorous PA (MVPA), and percentage of wake time in sedentary behavior (%SED) were measured. Two-by-four (sex–time) repeated measures analyses of variance were used to test changes in PA and %SED. Results In females and males, daily steps and MVPA increased from 2 to 4 months after ACL reconstruction (all P < 0.05) but not between other consecutive time points. %SED did not change between any consecutive time points. At 6 months, females walked fewer daily steps (P = 0.002; females: 7003 ± 2068; males: 10,406 ± 3277), spent fewer minutes in MVPA (P = 0.010; females: 31.3 ± 14.6; males: 54.9 ± 32.4), and spent more time in %SED (P = 0.003; females: 67.9 ± 7.4; males: 57.5 ± 9.5). Conclusions PA levels increased in females and males from 2 to 4 months after ACL reconstruction but not between other consecutive time points from before through 6 months after surgery. Females completed less PA and spent more time in sedentary behavior than males and may require greater monitoring to improve PA after ACL reconstruction. The disparity in PA and sedentary behavior across sex follows consistent previous findings that outcomes after ACL reconstruction are poorer in females compared with males.]]> Thu, 03 Apr 2025 00:00:00 GMT-05:00 00005768-202508000-00001 https://journals.lww.com/acsm-msse/fulltext/2025/08000/influence_of_running_speed_and_time.2.aspx Purpose Following anterior cruciate ligament reconstruction (ACLR), individuals present with significant and persistent deficits in surgical knee biomechanics during running. Little is known regarding the role of the hip and ankle in compensating for these knee-specific deficits. The purpose of this study was to characterize how limb (surgical and nonsurgical), time postoperatively (3.5–7 months [EARLY], 8–13 months [LATE]), and running speed influence lower extremity joint-specific and total work during running post-ACLR. Methods Fifty-six Division I collegiate athletes post-ACLR (EARLY: n = 41; LATE: n = 42; both: n = 27) completed running analyses at 2.68, 2.95, 3.35, 3.80, and 4.47 m·s−1 or up to their maximum comfortable speed. Linear mixed effects models assessed the influence of limb, speed, time post-ACLR, and their interactions on hip, knee, ankle, and total negative work and positive work. Results Surgical limb hip positive work was greater (0.044 J·kg−1 [95% CI = 0.015–0.074], P < 0.001) than the nonsurgical limb EARLY. Surgical limb ankle negative (−0.054 J·kg−1 [−0.093 to −0.015], P = 0.003) and positive work (−0.115 J·kg−1 [−0.168 to −0.063], P < 0.001) were less than the nonsurgical limb EARLY. Surgical limb knee negative (EARLY: −0.339 J·kg−1 [−0.382 to −0.296], P < 0.001; LATE: −0.222 J·kg−1 [−0.265 to −0.180], P < 0.001) and positive work (EARLY: −0.214 J·kg−1 [−0.246 to −0.182], P < 0.001; LATE: −0.142 J·kg−1 [−0.174 to −0.110], P < 0.001) were less than the nonsurgical limb. Total negative work and positive work followed the same pattern as the knee. Conclusions Athletes post-ACLR exhibited greater hip positive work and lesser ankle positive work and negative work during running of the surgical limb EARLY, which resolved LATE. Both knee and total negative work and positive work of the surgical limb were substantially less than the nonsurgical limb, which improved from EARLY to LATE, but between-limb asymmetries remained.]]> Thu, 06 Mar 2025 00:00:00 GMT-06:00 00005768-202508000-00002 https://journals.lww.com/acsm-msse/fulltext/2025/08000/achilles_subtendons_stiffness_differ_in_people.3.aspx Purpose Previous work showed altered mechanical properties of the Achilles tendon in the presence of tendinopathy, considering the Achilles tendon as a homogeneous structure with the gastrocnemius medialis (GM) subtendon representative of it. However, the Achilles tendon consists of three semi-independent structures: the GM, gastrocnemius lateralis (GL), and soleus (SOL) subtendons, each independently pulled by their respective muscle. The aim of this study was (i) to compare the mechanical properties of the different Achilles subtendons in humans in vivo by considering the force of each muscle within the triceps surae group and (ii) to determine whether the loss of stiffness in the presence of tendinopathy is specific to individual subtendons. We hypothesized that (i) stiffness would differ between subtendons in healthy participants and that (ii) the loss of stiffness in people with Achilles tendinopathy compared with healthy controls would not affect the three subtendons identically. Methods Fourteen participants with tendinopathy and 14 controls performed ramped isometric plantarflexions. Simultaneously, the elongation of the three subtendons was recorded, and an estimate of the force pulling on each was made (from muscle activation and volume). Stiffness was calculated from the individual muscle index of force–subtendon elongation relationships. Results Results showed that regardless of the group, SOL stiffness was significantly higher than stiffness of both gastrocnemii (muscle effect: P < 0.001). A muscle–group interaction showed specific loss of stiffness of GL in Achilles tendinopathy compared with controls (P = 0.029, d = 1.3), with no between-group difference for GM or SOL (both P > 0.925, d = 0.3). Conclusions This study supports the hypothesis that the biomechanical properties of the Achilles tendon differ between subtendons and further shows that the loss of stiffness in Achilles tendinopathy is specific to the GL subtendon.]]> Thu, 03 Apr 2025 00:00:00 GMT-05:00 00005768-202508000-00003 https://journals.lww.com/acsm-msse/fulltext/2025/08000/maternal_physical_activity,_fitness,_and_body.4.aspx Purpose This study aimed to 1) describe perinatal changes in physical activity (PA), physical fitness (PF), and body composition (BC) and 2) investigate prospective associations between PA and PF, and between PF and BC in metabolically high-risk women with gestational diabetes mellitus (GDM). Methods This secondary analysis of the MySweetheart trial included 211 women with GDM. Outcomes were measured at 24 to 32 wk of gestational age (GA) and at 1 yr postpartum. Physical activity was measured using accelerometer and BC with bioelectrical impedance analysis (fat mass [FM], fat-free mass [FFM]) or dual-energy X-ray absorptiometry (FM, visceral adipose tissue [VAT], lean mass [LM]; postpartum only). Regarding PF, handgrip strength and cardiorespiratory fitness (CRF) were assessed, the latter using the Chester step test to estimate the maximal oxygen uptake (V̇O2max). Models were adjusted for sociodemographic variables and BMI where applicable. Results Between pregnancy and the postpartum, sedentary time decreased (P < 0.001), whereas all PA intensities increased (all P < 0.001). CRF and handgrip strength did not change (both P ≥ 0.07), while FM and FFM decreased (both P < 0.001). Greater overall PA and moderate to vigorous PA during pregnancy were associated with better CRF and handgrip strength at 1 yr postpartum in unadjusted models only (P < 0.05). Higher V̇O2max was associated with lower FM and VAT, whereas higher handgrip strength was related to higher LM and FFM at 1 yr postpartum (all P < 0.001), before and after adjustments. Conclusions In high-risk women with GDM, higher PA during pregnancy correlated with greater PF at 1 yr postpartum only in the unadjusted, but not in the adjusted analyses. Higher PF levels were related to improved BC, highlighting their importance in the perinatal period.]]> Fri, 04 Apr 2025 00:00:00 GMT-05:00 00005768-202508000-00004 https://journals.lww.com/acsm-msse/fulltext/2025/08000/exercise_rescues_blood_brain_barrier_structural.5.aspx Purpose Blood–brain barrier (BBB) dysfunction is implicated in various neurodegenerative diseases, including Alzheimer’s disease and frontotemporal dementia. Over the past decades, numerous studies have suggested that exercise can mitigate neurodegenerative processes by improving mitochondrial function. Recently, we demonstrated that exercise could reverse hippocampus-associated memory deficits and reduce BBB leakage in a modified two-kidney, one-clip (2K1C) hypertensive animal model. Based on these findings, we hypothesize that exercise restores BBB integrity in hypertensive animal models. Methods Hypertension was induced in C57BL/6 mice via 2K1C surgery. After 3 wk of hypertension induction, mice underwent moderate-intensity treadmill exercise for 5 wk. Subsequently, brain tissues were collected for immunofluorescence staining and immunoblotting analyses to assess changes in BBB structure and mitochondria-related protein expression. Results Exercise restored hypertension-induced reductions in blood vessel density within the hippocampus. Additionally, it repaired BBB structural impairments, as evidenced by increased levels of Claudin-5 colocalization with blood vessels, enhanced perivascular astrocyte levels, and improved perivascular AQP-4 protein expression. An immunoblotting analysis revealed that exercise upregulated the PGC-1α/Nrf1/UCP-2 pathway in the 2K1C hypertensive model. However, exercise did not significantly affect Drp-1 expression. Conclusions Exercise alleviates BBB leakage by restoring structural integrity to the BBB. These improvements may be mediated through the enhancement of mitochondrial biogenesis.]]> Wed, 05 Mar 2025 00:00:00 GMT-06:00 00005768-202508000-00005 https://journals.lww.com/acsm-msse/fulltext/2025/08000/changes_in_v_o2max_after_6_wk_of_intensity.6.aspx Purpose This study characterized central and peripheral adaptations to domain-specific endurance exercise training. Methods Eighty-four young healthy participants were randomly assigned to age- and sex-matched groups of: continuous cycling in the 1) moderate-intensity (MOD), 2) lower heavy-intensity (HVY1), and 3) upper heavy-intensity (HVY2) domain; interval cycling in the 4) severe-intensity domain (i.e., high-intensity interval training (HIIT), and 5) extreme-intensity domain (i.e., sprint-interval training (SIT)); or 6) control (CON). Two 3-wk phases of training (three sessions per week) were performed. All training protocols, except SIT, were work matched. Results Maximal oxygen uptake (V̇O2max), maximal cardiac output (Q˙max), derived maximal arterial–venous oxygen difference (a-vO2diff), blood volume (BV), plasma volume (PV), and near-infrared spectroscopy (NIRS)–derived muscle oxidative capacity (τOxCap) were measured and compared at PRE and POST. The largest change in V̇O2max occurred in HIIT (0.43 ± 0.20 L·min−1), which was greater than CON (0.02 ± 0.08 L·min−1), MOD (0.11 ± 0.19 L·min−1), HVY1 (0.24 ± 0.18 L·min−1), and SIT (0.28 ± 0.21 L·min−1) (P < 0.05) but not HVY2 (0.36 ± 0.14 L·min−1) (P > 0.05). Changes in Q˙max were observed in HVY1 (1.6 ± 0.5 L·min−1), HVY2 (3.0 ± 0.6 L·min−1), HIIT (2.9 ± 1.2 L·min−1), and SIT (1.8 ± 1.4 L·min−1) (P < 0.05) but not in MOD (1.2 ± 0.3 L·min−1) and CON (0.1 ± −0.5 L·min−1) (P > 0.05). HVY2 and HIIT produced significant changes in BV (438 ± 101 and 302 ± 38 mL) and PV (198 ± 92 and 158 ± 51 mL), respectively (P < 0.05), whereas other groups did not. Conclusions No significant peripheral adaptations (i.e., τOxCap and a-vO2diff) were observed in any group (P > 0.05). The results indicate that higher training intensities (i.e., HVY2 and HIIT) produce larger changes in V̇O2max, which is supported predominantly by central adaptations. In addition, results suggest that, despite nonsignificant changes, the contribution of peripheral components to changes in V̇O2max should not be dismissed.]]> Thu, 06 Mar 2025 00:00:00 GMT-06:00 00005768-202508000-00006 https://journals.lww.com/acsm-msse/fulltext/2025/08000/peripheral_and_central_hemodynamic_responses_to.7.aspx Purpose Non-Hispanic Black (NHB) women in the United States exhibit higher prevalence and mortality rates from cardiovascular diseases compared with non-Hispanic White (NHW) women. Previous studies in NHB men have demonstrated impaired vascular function at rest and during exercise; however, to date, no studies have investigated the hyperemic responses during exercise in NHB women. Therefore, we tested the hypothesis that, compared with NHW women, NHB women would present an attenuated increase in forearm blood flow (FBF) and forearm vascular conductance (FVC) during steady-state rhythmic handgrip exercise. Methods FBF (duplex Doppler ultrasound) and central hemodynamics including mean arterial pressure (MAP; finger photoplethysmography) were measured in healthy young NHW (n = 16) and NHB (n = 14) women during rhythmic handgrip exercise performed at 15%, 30%, and 45% of maximal voluntary contraction (MVC). Results FVC (calculated as FBF/MAP), FBF, and MAP were not different between groups at rest (FVC: 52 ± 13 mL·min−1·100 mm Hg−1 in NHW women vs 56 ± 14 mL·min−1·100 mm Hg−1 in NHB women; P = 0.43). There was an intensity-dependent increase in FBF and FVC during exercise in both groups, but there was no difference between the groups (e.g., FVC at 45% MVC; NHW: 304 ± 55 mL·min−1·100 mm Hg−1, NHB: 351 ± 121 mL·min−1·100 mm Hg−1, interaction P = 0.257). MAP responses during exercise were also not different between groups (e.g., ΔMAP at 45% MVC; NHW: 7 ± 6 mm Hg, NHB:8 ± 6 mm Hg, P = 0.553). In addition, all central hemodynamics during exercise and flow-mediated dilation were comparable between the groups. Conclusions Collectively, these findings indicate that the hyperemic responses to rhythmic handgrip exercise are not different between young, healthy NHB and NHW women.]]> Thu, 06 Mar 2025 00:00:00 GMT-06:00 00005768-202508000-00007 https://journals.lww.com/acsm-msse/fulltext/2025/08000/oxygen_uptake_dynamics_conform_to_acute_changes_in.8.aspx Purpose This study aimed to investigate whether muscle excitation during constant-work rate (WR) cycling is connected with total[Hb + Mb] and whether they interact with the oxygen uptake (V̇O2) dynamics. Methods In experiment 1, 10 participants performed a 21-min constant-WR (CWR) within the heavy-intensity domain (i.e., 75% of the difference between the gas exchange threshold and the maximal metabolic steady state) and a ramp-to-constant-WR (rCWR) to the same WR. CWR and rCWR were repeated twice and allocated in random order. In experiment 2, nine participants performed a double-constant-WR (dCWR) consisting of a 21-min exercise bout, a short 20-s break, and a second bout of 21 min within the heavy domain. V̇O2, EMG root-mean-square (EMGRMS), total[Hb + Mb], and deoxygenated hemoglobin ([HHb]) were collected from the vastus lateralis. The EMGRMS/total[Hb + Mb] and the EMGRMS/[HHb] ratios were computed. Results The EMGRMS was lower at minutes 1 and 7 and total[Hb + Mb] higher at minute 1 during the rCWR compared with the CWR condition (all P < 0.05). EMGRMS displayed an overshoot at minute 1, which was different from minute 21 during the CWR condition (P < 0.05). EMGRMS did not display an overshoot after the 20-s break during the dCWR condition. The EMGRMS/total[Hb + Mb] inverted ratio was not different from V̇O2 (%). The EMG magnitude of frequencies ranging from ~30 to 90 Hz was initially higher and decreased over time (P < 0.05). Conclusions This study demonstrated that EMGRMS-derived muscle excitation can be reduced by exercise protocols that promote higher total[Hb + Mb]. Furthermore, the interaction between muscle excitation and total[Hb + Mb] matched with systemic V̇O2. Whether electromyography (EMG)-derived muscle excitation and near-infrared spectroscopy (NIRS)–derived total hemoglobin and myoglobin concentration (total[Hb + Mb]) are linked during cycling exercise is unknown.]]> Thu, 06 Mar 2025 00:00:00 GMT-06:00 00005768-202508000-00008 https://journals.lww.com/acsm-msse/fulltext/2025/08000/trends,_characteristics,_and_mortality_of_u_s_.9.aspx Purpose The aim of the study was to describe trends, characteristics, and mortality associations of U.S. adults unable to do aerobic leisure-time physical activity (LTPA) from 1998 to 2018. Methods We used data from 21 U.S. National Health Interview Survey annual updates. Logistic binary regressions were used to estimate odds ratios (OR) and Cox proportional regression models to estimate hazard ratios (HR). People unable to do aerobic LTPA was self-reported. Results From a total of 621,499 participants pooled, 10,554 (1.70%) were unable to do PA. Adults who were older than 65 yr (OR = 14.37, 95% confidence interval [CI] = 12.69–16.28), unemployed (OR = 15.61, 95% CI = 14.20–17.17), reported a bad self-rated health (OR = 45.69, 95% CI = 39.52–52.83), and had limitations with instrumental activities of the daily living (OR = 16.51, 95% CI = 15.68–17.38) had a higher risk of being unable to do aerobic LTPA. During a mean follow-up time of 10.36 yr, 5137 participants (50.44%) who were unable to do aerobic LTPA died. They had a higher mortality risk for all-cause (HR = 1.23, 95% CI = 1.18–1.28) mortality compared with the participants who were able to do aerobic LTPA. Adults unable to do aerobic LTPA had an increased risk of all-cause mortality (HR = 1.13, 95% CI = 1.09–1.19) than those who were able but did not perform aerobic LTPA. Conclusions U.S. adults unable to perform aerobic LTPA showed a higher risk of all-cause mortality compared with adults who were able to perform aerobic LTPA, and even compared with those who were physically inactive.]]> Fri, 07 Mar 2025 00:00:00 GMT-06:00 00005768-202508000-00009 https://journals.lww.com/acsm-msse/fulltext/2025/08000/cardiometabolic_benefit_of_replacing_sedentary.10.aspx Purpose The cardiometabolic benefits of replacing sedentary time with light-intensity physical activity (LIPA) are unclear. We studied the associations of hypothetically reallocating sedentary time toward LIPA with changes in cardiometabolic risk factors using thigh-worn accelerometery. We also explored whether reallocation effects differed across subgroups with low, moderate, and high sedentary time and compared proportionally similar reallocations to either LIPA or moderate-to-vigorous physical activity. Methods We assessed physical behaviors across 8 consecutive days using thigh-worn accelerometers among adults from the Nijmegen Exercise Study. Multiple cardiometabolic risk factors were assessed and categorized as 1) anthropometrics, 2) cardiovascular biomarkers, and 3) glucose metabolism. Reallocation effects were estimated for each cardiometabolic risk factor using compositional isotemporal substitution models adjusted for confounders. Analyses were repeated in sedentary time subgroups, that is, <8.5, 8.5–10, and >10 h·d−1. Results We included 1041 participants (64 (standard deviation 11) yrs; 39.5% female). Reallocating sedentary time toward LIPA was associated with improvements in anthropometrics, some cardiovascular biomarkers, and glucose metabolism; for example, replacing 60 min·d−1 of sedentary time with LIPA was associated with improvements in body mass index (−0.28 (−0.42 to −0.13) kg·m−2), estimated glomerular filtration rate (0.68 (0.15 to 1.20) mL·min−1·1.73m−2), and glucose (−0.05 (−0.08 to −0.03) mmol·L−1). Trends suggested that reallocation benefits were strongest in those with >8.5 h·d−1 of sedentary time. Proportionally similar replacements of sedentary time with either LIPA or moderate-to-vigorous physical activity were associated with similar cardiometabolic benefits. Conclusions Reallocation of sedentary time to LIPA was associated with improvements in cardiometabolic risk factors, predominantly in anthropometrics and glucose metabolism, with greater benefits in the most sedentary individuals. Time reallocation from sedentary time to LIPA may be an effective and arguably feasible strategy to improve population-wide cardiometabolic health.]]> Fri, 14 Mar 2025 00:00:00 GMT-05:00 00005768-202508000-00010 https://journals.lww.com/acsm-msse/fulltext/2025/08000/beetter_aging__short_term_dietary_nitrate.11.aspx Purpose Dietary nitrate (NO3−) supplementation has been shown to improve skeletal muscle contractile function and reduce fatigue, potentially due to alterations in skeletal muscle Ca2+ handling/sensitivity. Because aging muscle can have impaired Ca2+ handling, the aim of the study was to evaluate the effects of dietary NO3− supplementation on muscle contractile properties in young and older adults. Methods Eleven older (69 ± 4 yr, O) and 11 young (26 ± 2 yr, YG) adults consumed either NO3−-rich beetroot juice (BR) or placebo (PLA), for 7 d. After supplementations, plantar flexors of dominant leg were evaluated as follow: a) maximal voluntary isometric contraction (MVIC), b) potentiated single twitches (Twpot) and double twitches electrical stimulations at the frequency of 100 Hz (Db100) on the tibial posterior nerve, c) a fatigue isometric (70% of MVIC) test until exhaustion. The force–frequency relationship was assessed with trains of electrical pulses across a wide range of frequencies on the muscle belly of the nondominant leg. Results BR supplementation increased plasma [NO3−] and nitrite [NO2−] in both O and YG compared with PLA (more than sevenfold; all P ≤ 0.02). No changes were observed in MVC, Twpot, and Db100 force after BR compared with PLA in both YG and O. Only in O, Db100 area under the curve (−7 ± 6 N·s change from PLA) and half relaxation time (−0.05 ± 0.06 s change from PLA) were significantly reduced, and time to exhaustion (+32 ± 43 s change from PLA) was significantly longer (all P < 0.02) after BR. In O, BR also significantly increased submaximal force produced by trains of electrical pulses (P < 0.001). Conclusions NO3− supplementation positively affects muscle contractile proprieties, submaximal electrically evoked force production, and fatigue resistance in older adults, whereas these positive results were not found in young.]]> Tue, 18 Mar 2025 00:00:00 GMT-05:00 00005768-202508000-00011 https://journals.lww.com/acsm-msse/fulltext/2025/08000/voluntary_exercise_attenuates_tumor_growth_in_a.12.aspx Purpose To examine the effects of voluntary wheel running on tumor growth and explore potential intratumoral molecular pathways responsible for the beneficial effects of voluntary wheel running on tumor formation and progression in a mouse model of castration-resistant prostate cancer (CRPC). Methods Male immunodeficient mice (SCID) were castrated and subcutaneously inoculated with human CWR-22RV1 cancer cells to construct CRPC xenograft model before assigned to either voluntary wheel running (VWR) or sedentary (SED) group (n = 6/group). Tumor size was measured and calculated throughout the study. After 3 wk, tumor tissues were collected. mRNA expression of markers of DNA replication, androgen receptor (AR) signaling, and mitochondrial dynamics was determined by quantitative real-time polymerase chain reaction. Protein expression of mitochondrial dynamics was determined by Western blotting. Finally, transcriptomics analysis was performed using the tumor tissues. Results Voluntary wheel running resulted in smaller tumor volume at the initial stage and attenuated tumor progression throughout the time course (P < 0.05). The reduction of tumor volume in the VWR group coincided with lower mRNA expression of DNA replication markers (MCM2, MCM6, and MCM7), AR signaling (ELOVL5 and FKBP5), and regulatory proteins of mitochondrial fission (Drp1 and Fis1) and fusion (MFN1 and OPA1) when compared with the SED group (P < 0.05). RNA sequencing data further revealed that pathways related to angiogenesis, extracellular matrix formation, and endothelial cell proliferation were downregulated. Conclusions Three weeks of voluntary wheel running was effective in delaying tumor formation and progression, which coincided with reduced transcription of DNA replication, AR signaling targets, and mitochondrial dynamics. We further identified a downregulation in molecular pathways related to angiogenesis that may be responsible for the delayed tumor formation and progression by voluntary wheel running.]]> Wed, 26 Mar 2025 00:00:00 GMT-05:00 00005768-202508000-00012 https://journals.lww.com/acsm-msse/fulltext/2025/08000/in_vivo_biomechanical_interactions_between_bones,.13.aspx Purpose Stationary cycling is essential in rehabilitation programs for various patient groups, such as knee osteoarthritis and cruciate ligament injuries and reconstruction. The study aimed to measure in vivo the 3D rigid-body and articular surface kinematics of the knee and the patellar tendon orientations during stationary cycling and isolated flexion–extension exercise in healthy young adults using a model-based tracking approach with dual-plane fluoroscopy. Methods Ten healthy left knees were imaged by computed tomography and magnetic resonance imaging to reconstruct subject-specific volumetric bone–cartilage models. The 3D rigid-body and articular surface kinematics and patellar tendon angles during stationary cycling and isolated knee flexion–extension exercise were measured in vivo using a dual-plane fluoroscopy with a voxel-based registration method, compared between tasks and between power and recovery phases. Results Significant differences in the rigid-body and surface kinematics and patellar tendon orientations were found between the power and recovery phases and between the power phase and isolated knee extension. Compared with the recovery phase, the power phase showed significantly greater external rotations, adductions, and posterior translations for flexions greater than 45° (P < 0.05) with significantly more posterior medial and lateral contact positions for flexion angles less than 45° (P < 0.05) and more vertical patellar tendon orientations for flexion angles lesser than 60° (P < 0.05). Conclusions The contact locations and loads on the posterior half of the tibial articular surface during the first half of the power phase indicate that stationary cycling as a daily and rehabilitative exercise is safe for people with anterior medial knee osteoarthritis.]]> Fri, 28 Mar 2025 00:00:00 GMT-05:00 00005768-202508000-00013 https://journals.lww.com/acsm-msse/fulltext/2025/08000/bone_health_of_female_elite_cyclists_is.14.aspx Purpose Many elite road-race cyclists have low areal bone mineral density (aBMD) as previously shown by dual-energy x-ray absorptiometry (DXA). However, aBMD provides limited insight into bone quality. Therefore, this cross-sectional study aimed to assess volumetric BMD (vBMD), bone microarchitecture, and bone strength in elite road-race cyclists using high-resolution peripheral computed tomography (HR-pQCT), along with aBMD measured by DXA. Methods Twenty female elite (Tier 3/4) road-race cyclists (21 ± 2 yr; body mass index, 20.8 ± 1.6 kg·m−2) had DXA scans at the hip, lumbar spine, and total body to assess aBMD, and HR-pQCT scans at the distal radius and tibia to assess vBMD, bone microarchitecture, and failure load. Z-scores were calculated for all outcomes, with Z-scores <−1 considered as low or impaired. The risk of low energy availability was assessed using the Low Energy Availability in Females Questionnaire. Results Low aBMD was observed in 20%, 25%, 35%, and 10% of the participants at the hip, femoral neck, lumbar spine, and total body, respectively. Low total vBMD was present in 45% and 40% at the distal radius and tibia, respectively. With regard to bone microarchitecture, the tibial cortical area and tibial cortical thickness were low in 40% and 60% of the participants, respectively, and number and thickness of trabeculae at the tibia were low in 40% and 30% of the participants. The impairments were less pronounced at the distal radius. Failure load was low in 15% (radius) and 20% (tibia) of the participants. Conclusions Along with low aBMD, a substantial proportion of female elite cyclists had impaired bone microarchitecture, mainly characterized by a low cortical area and thickness and low trabecular number and thickness, especially at the distal tibia.]]> Thu, 03 Apr 2025 00:00:00 GMT-05:00 00005768-202508000-00014 https://journals.lww.com/acsm-msse/fulltext/2025/08000/temporal_trends_and_projected_daily_step_count.15.aspx Purpose This study aimed to describe trends in the daily number of steps taken by the Japanese population from 1995 to 2019, using data from the National Health and Nutrition Survey Japan (NHNS-J), and to project step counts for 2032, the target year of the Health Japan 21 (HJ21) third term, while assessing the feasibility of national physical activity goals. Methods We analyzed individual, pedometer-based daily step count data from 213,924 participants between 1995 and 2019. Age-adjusted average daily step counts were calculated, then linear regression model was used to project daily step counts for 2032, stratified by age (20–64 yr, 65+ yr) and gender. Results The average number of steps taken by the Japanese population has shown a consistent decline since 2000. The projected daily step counts (95% confidence interval [CI]) for 2032 were as follows: 7499 (6854–8144) steps per day for men 20–64 yr old, 5038 (4091–5985) steps per day for men 65+ yr old, 6073 (5277–6869) steps per day for women 20–64 yr old, and 4620 (3749–5490) steps per day for women 65+ yr old. Significant declines were observed in women 20–64 yr old (beta = −45.8 steps per year, 95% CI = −86.4 to −15.2). The new step count targets set by HJ21 (8000 steps per day for younger adults and 6000 steps per day for older adults) are 6.1% to 26.9% higher than the projected values, particularly for women. Conclusions Daily step counts in Japan have shown a long-term decline, particularly among women. The projected decline in step counts indicates that the new step targets set by HJ21 may be challenging to achieve, particularly for women. Future public health initiatives should prioritize promoting physical activity in this population.]]> Fri, 01 Aug 2025 00:00:00 GMT-05:00 00005768-202508000-00015 https://journals.lww.com/acsm-msse/fulltext/2025/08000/muscular_strength_in_cancer_patients__proposed.16.aspx Purpose The aim of this study is to propose muscular strength normative data tables for the cancer population and observe the effects of exercise training on categorical placement. Methods Data from cancer survivors (n = 659) encompassing various cancer types across all cancer stages were used for this study. Participants completed assessments to estimate one-repetition maximum (1RM) for both chest press and leg press, in addition to a test of maximum effort dominant handgrip strength. Strength-to-weight ratio (SWR) and handgrip strength values were divided into categories by sex and age and compared with normative values from the apparently healthy population as reported by the American College of Sports Medicine. Results Comparison of mean SWR and handgrip strength values for the cancer population to the apparently healthy normative data resulted in each age/sex group being classified as “average” or lower. Of the 30 age/sex classification groups for the cancer population, 23 demonstrated mean strength values in the lowest category of their respective assessment. Conclusions Normative data derived from the apparently healthy population may not be an appropriate comparison for the cancer population and may not be sensitive enough to detect categorical improvements in muscular strength resulting from exercise training. We provide an initial data set that could serve as a first step in the development of normative strength data for this population. With the increasing implementation of oncology-based exercise rehabilitation, there is a need for normative strength values specific to the cancer population.]]> Mon, 10 Mar 2025 00:00:00 GMT-05:00 00005768-202508000-00016 https://journals.lww.com/acsm-msse/fulltext/2025/08000/a_moderate_intensity_interval_training_block.17.aspx Purpose This study compared the physiological effects of a moderate-intensity interval training (MIT) microcycle followed by an active recovery period (collectively termed MITblock) with a time-matched regular training period (REG) during the general preparation phase in well-trained cyclists. Methods Using a randomized crossover design, 30 well-trained male cyclists (maximal oxygen consumption (V̇O2max), 70.5 (4.6) mL·min−1·kg−1) completed both MITblock and REG. The MIT microcycle involved six interval sessions over 7 d with 5–7 × 10–14-min work intervals at a rating of perceived exertion (RPE) of 14–15 on the Borg 6–20 scale. A 6-d active recovery period followed before physiological testing. During REG, cyclists performed their regular preparatory-phase training routine, which primarily involved low-intensity exercise. Specific guidelines included completing either two MIT sessions or one MIT session and one high-intensity interval session per week. Endurance performance indicators assessed included changes in 15-min maximal average power output (PO15min), power output at 4 mmol·L−1 [blood lactate] (PO4mmol), 1-min peak power output during incremental testing (POV̇O2max), and V̇O2max. Results Although the Training Impulse (TRIMP) score was not different between MITblock and REG (1944 (436) vs 1800 (232), respectively; P = 0.27), MITblock resulted in significantly greater improvements than REG in PO4mmol (4.0% (4.4%) vs −1.3% (3.7%), P < 0.01), POV̇O2max (2.5% (4.5%) vs −0.7% (3.9%), P < 0.01), and V̇O2max (2.0% (3.9%) vs 0.0% (3.5%), P = 0.05). Changes in PO15min were not statistically different between MITblock and REG (3.9% (8.3%) vs 0.2% (6.8%), P = 0.14). During MIT intervals, rating of perceived exertion was 14.4 (0.3), corresponding to 66% (5%) of POV̇O2max, 85% (3%) of maximal heart rate, and 2.8 (1.1) mmol·L−1 [blood lactate]. Conclusions Six moderate-intensity interval sessions over 7 d, followed by a 6-d active recovery period, induce improvements in endurance performance indicators compared with a time-matched regular training period in well-trained cyclists.]]> Tue, 18 Mar 2025 00:00:00 GMT-05:00 00005768-202508000-00017 https://journals.lww.com/acsm-msse/fulltext/2025/08000/physiological_determinants_of_v_o2max_increase.18.aspx Purpose This study aimed to examine central and peripheral physiological adaptations contributing to increases in maximal oxygen uptake (V̇O2max) following a 12-wk vigorous endurance exercise program in healthy, older and young adults. Methods Fourteen participants (7 older: 68 ± 7 yr and 7 young: 26 ± 7 yr; 9 males and 5 females) engaged in a cycling training program three times a week for 45 min at ~70%V̇O2max. Changes in V̇O2max, cardiac function, V̇O2 extraction, muscle capillarization, and mitochondrial content from pre- to post-training were examined. Results The increase in V̇O2max from pre- to post-training for all participants (20% ± 8%) was accompanied by increases in maximal cardiac output (Q˙max; 15% ± 11%), maximal stroke volume (SVmax; 14% ± 12%), muscle fiber cross-sectional area (CSA; 17% ± 21%) and perimeter (P; 7% ± 9%), citrate synthase (CS) activity (144% ± 175%), individual capillary-to-fiber ratio (C:Fi; 32% ± 17%), capillary-to-fiber perimeter exchange index (CPFE: 30% ± 15%), capillary contact (CC; 38% ± 20%), capillary density (CD; 22% ± 17%), and arteriovenous O2 difference (a-vO2diff; 4% ± 6%) (P < 0.05 for all). No training-related variation existed for maximal heart rate (HRmax; −1% ± 4%; P = 0.448). Changes in V̇O2max were positively correlated with Q˙max (r = 0.830: P < 0.001), SVmax (r = 0.655; P = 0.011), CD (r = 0.546; P = 0.043), and CS activity (r = 0.630; P = 0.021). No significant correlations were found for changes in V̇O2max and changes in HRmax, a-vO2diff, muscle fiber CSA and P, CC, C:Fi, and CPFE (P > 0.05 for all). Conclusions Cardiorespiratory fitness improvements were primarily determined by enhancement in central (i.e., cardiac function) and peripheral (i.e., vascularization) adaptations within the V̇O2 transport system as well as the upregulation of mitochondrial aerobic enzymatic activity (i.e., CS activity) at the intracellular level.]]> Fri, 21 Mar 2025 00:00:00 GMT-05:00 00005768-202508000-00018 https://journals.lww.com/acsm-msse/fulltext/2025/08000/hamstrings_muscle_architecture_and_morphology.19.aspx Purpose This study investigated the effects of a 6-wk eccentrically biased training intervention between Romanian deadlift (RDL) and Nordic hamstring exercises (NHE) on regional hamstring muscle architecture and morphology. Methods Participants were randomly allocated to an RDL or NHE intervention group and trained twice per week for 6 wk followed by a 2-wk detraining period. Biceps femoris long head (BFlh) architecture (fascicle length (FL) and pennation angle (PA)) and muscle thickness (MT) were measured using extended-field-of-view ultrasound. Anatomical cross-sectional areas (ACSA) of BFlh, semimembranosus, and semitendinosus were also assessed via ultrasound. Muscle architecture and morphology were measured proximally, in the middle, and distally along the thigh. Separate linear mixed-effects models were run for each outcome. Results Thirty-two healthy participants (15 females, 17 males) aged 20.8 (0.9) yr were enrolled and allocated to RDL (n = 16) or NHE (n = 16) groups. Following the intervention, BFlh FL increased (0.80 (0.6–1.0) cm (9%), P < 0.001), whereas PA decreased uniformly across all regions (−1.2° (−1.5° to −0.9°) (10%), P < 0.001) and MT did not change (P = 0.29). Both BFlh FL and PA returned to baseline after detraining. No differences were observed between groups for changes in FL (P = 0.55), PA (P = 0.74), or MT (P = 0.48). Hamstrings ACSA increased after the intervention (0.78 cm2 (0.45–1.11 cm2) (10%), P < 0.001) and remained elevated after detraining. There were no significant differences in ACSA between groups after the intervention (P = 0.60). Conclusions Changes in FL, PA, and ACSA are consistent between an eccentrically biased RDL and NHE intervention. These findings provide practitioners choice in exercise selection for eliciting adaptations relevant to hamstring injury prevention.]]> Wed, 14 May 2025 00:00:00 GMT-05:00 00005768-202508000-00019 https://journals.lww.com/acsm-msse/fulltext/2025/08000/duty_factor_dominates_stride_frequency_to_modify.20.aspx Background/purpose Adjusting running style can influence musculoskeletal loading, thereby altering injury risk. Duty factor, defined as the ratio of contact time to stride time, along with stride frequency, have been linked to peak loading in previous studies, although their specific influences remain unclear. This study elucidates how duty factor and stride frequency, both individually and in tandem, affect peak loading at an individualized constant speed, enhancing our understanding of how changes in running pattern affect musculoskeletal loading. Methods Nineteen female novice runners ran on treadmill at 90% of their individually preferred running speed. Subjects were instructed to adjust duty factor and/or stride frequency according to a specific protocol. Ground reaction forces and motion capture data were recorded. Peak loading was assessed through maximal vertical ground reaction force, maximal resultant joint reaction forces, and maximal extensor and flexor moments of the lower limb joints using an inverse dynamics approach. Mixed-effects models were utilized to analyze the individual and combined effects of duty factor and stride frequency on peak loading. Results and Discussion Increasing duty factor consistently reduced peak loading across all metrics except hip extensor and flexor moments, which showed an increase. In contrast, the relationship between stride frequency and peak loading varied across loading metrics. Increasing stride frequency reduced peak knee and hip extensor moments and had no effect on maximal vertical ground reaction force or peak joint reaction forces, but increased peak hip flexor moment. Surprisingly, when controlled for duty factor, stride frequency also became a determinant of maximal vertical ground reaction force and peak joint reaction forces, leading to unexpected increases in peak loading as stride frequency increased. Conclusions This study establishes duty factor as the primary factor in modulating peak loading in running. Stride frequency may also affect peak loading, but its effect varies based on individual characteristics and the metric considered.]]> Fri, 04 Apr 2025 00:00:00 GMT-05:00 00005768-202508000-00020 https://journals.lww.com/acsm-msse/fulltext/2025/08000/effects_of_intense_physical_training_on_left.21.aspx Purpose We sought to evaluate the effect of intensive physical training on left ventricular (LV) hemodynamic forces (HDF) in athletes. Methods Forty professional endurance athletes were evaluated at the beginning of their training cycle (off-season) and after a period of aerobic isotonic dynamic exercise (peak training period) using cine cardiac magnetic resonance (CMR). Images were analyzed off-line using dedicated software. LV HDF for the whole cardiac cycle and the different cardiac phases were measured. Standard statistics were used to compare off-season and peak training period values. Results The average sport experience was 11 ± 7 yr. There were no differences in LV volumes, stroke volume, LV ejection fraction, and LV mass between off-season and peak training CMR. Similarly, there were no changes induced by physical training in the strain parameters. Physical training induced a significant increase of the longitudinal HDF (18.7 vs 21.2, P = 0.023) and an increase of the transverse HDF (3.4 vs 4.0, P = 0.048) throughout the entire heartbeat. After physical training, the peak values and the hemodynamic work (expressed as area under the curve) of the first part of the systole were significantly higher compared with off-season values (63.9 vs 53.9 (P = 0.034); 4.67 vs 3.79 (P = 0.015), respectively). The difference in the elastic rebound between off-season and peak training (−0.22 vs −0.37) did not reach statistical significance (P = 0.056). Conclusions Intense physical training induces an increase in LV HDF throughout the entire heartbeat, independent from geometric cardiac remodeling. The first part of the systole is the phase of the cardiac cycle that is mostly improved by intense physical training.]]> Wed, 14 May 2025 00:00:00 GMT-05:00 00005768-202508000-00021 https://journals.lww.com/acsm-msse/fulltext/2025/08000/breaking_the_cycling_hour_record__is_there_still.22.aspx No abstract available]]> Thu, 24 Apr 2025 00:00:00 GMT-05:00 00005768-202508000-00022 https://journals.lww.com/acsm-msse/fulltext/2025/08000/response.23.aspx No abstract available]]> Mon, 05 May 2025 00:00:00 GMT-05:00 00005768-202508000-00023