Christer Malm

Scopus Publications

Fine-needle muscle microbiopsy: a feasible and well-tolerated alternative for skeletal muscle sampling
Johan Jakobsson, Karin Strigård, Apostolos Theos, Michael Svensson, Christer Malm
Frontiers in Physiology, 2026
Background Conventional muscle biopsy techniques, such as the Bergström method, require large tissue samples and skin incisions. Fine-needle muscle microbiopsy offers a minimally invasive alternative, but data on tolerability are lacking. We aimed to present a refined minimally-invasive muscle microbiopsy protocol using a 20-gauge needle with topical anaesthesia and compare perceived pain with routine venipuncture. Methods Twenty-six healthy adults (50% female) underwent vastus lateralis microbiopsy using a 20-gauge needle (0.9 mm). Pain was assessed immediately after the microbiopsy and a venous blood draw using a 21-gauge needle, with the visual analogue scale (VAS). Procedures were randomized. Results Seventy-eight microbiopsies were successfully obtained. Mean pain scores were low for both procedures (microbiopsy: 1.0 ± 0.9; venipuncture: 1.4 ± 1.2) with no significant difference (P = 0.311). Most participants reported minimal or low discomfort (VAS ≤3) from the microbiopsy. Conclusion Fine-needle muscle microbiopsy using a 20-gauge needle is well tolerated, with pain comparable to routine venipuncture. This approach substantially reduces invasiveness compared to traditional biopsies while providing adequate material for proteomic analysis. These findings support its ethical and practical application in sensitive populations and longitudinal research.
Health-enhancing physical activity induce beneficial skeletal muscle mitochondrial adaptations in individuals with rheumatoid arthritis
Emily Shorter, Elena Ossipova, Estela Santos Alves, Helena Idborg, Jone Vanluyten, et al.
Clinical Rheumatology, 2025
Objective Rheumatoid arthritis (RA) is a common chronic systemic inflammatory disease that causes musculoskeletal impairments and fatigue. Physical activity is recommended for individuals with RA, and health-enhancing physical activity (HEPA) has been shown to improve health perception and physical fitness in this group. However, the molecular adaptations of skeletal muscle in response to an exercise intervention are still unexplored in individuals with RA. This study aimed to assess the skeletal muscle response to a 2-year HEPA intervention in individuals with RA. Methods Thirteen individuals with RA (65 ± 2 years old, 13 ± 2 years disease duration) participated. The 2-year HEPA intervention involved 150 min of weekly moderately intense aerobic activity and twice-weekly circuit training. Practical and theoretical physiotherapist support was available the first year, but not the second year. Skeletal muscle biopsies, functional assessments, and mass spectrometry-based proteomics analysis were conducted. Results Compliance was high the first year but dropped significantly the second year. Functional improvements in strength, endurance, and lower extremity muscle function (TST) were observed after year 1. Proteomics analysis revealed significant enrichment of mitochondrial proteins including COX8A, citrate synthase, M2OM, NDUFA6, NDUFS2, and VDAC3 after year 1, indicating positive muscle adaptations. However, these changes regressed to baseline levels by year 2. Conclusion HEPA can induce beneficial mitochondrial adaptations in skeletal muscle of individuals with RA. However, insufficient compliance and progression in HEPA exercise load led to a reversal of these adaptations. Continuous support and motivation are crucial for maintaining and progressing exercise levels and muscle health in individuals with RA. Key points• Health-enhancing physical activity (HEPA) can induce beneficial mitochondrial adaptations in the skeletal muscle proteome of individuals with RA.• Positive effects on mitochondrial protein levels aligned with the participants compliance to the HEPA intervention.• Results emphasizes that sustaining and progressing exercise regimen is crucial to maintain beneficial adaptations for individuals with RA.
Can response to ADHD medication be predicted?
Maria M. Lilja, Paul Lichtenstein, Eva Serlachius, Jyoti Bhagia, Kerstin Malmberg, et al.
European Child and Adolescent Psychiatry, 2025
Predictors for the pharmacological effect of ADHD medication in children and adolescents are lacking. This study examined clinically relevant factors in a large (N = 638) prospective cohort reflecting real-world evidence. Children and adolescents aged 6–17 diagnosed with ADHD were evaluated at baseline and three months following ADHD medication initiation. The outcome was measured as a reduction in total SNAP-IV (Swanson Nolan and Pelham teacher and parent rating scale) score at three months compared to baseline. Outcome groups were defined as Responders (≥ 40% reduction), Intermediate Responders (≥ 20 to < 40% reduction), and Non-responders (< 20% reduction). Included independent variables were the Autism Spectrum Questionnaire (ASSQ), the Spence Children’s Anxiety Scale (SCAS), the Pediatric Side Effect Checklist (P-SEC), anthropometrics measures, geographical region, relative age, Children´s Global Assessment Scale (CGAS), Intelligence quotient (IQ), pharmacological treatment initiation month, ADHD symptom severity, ADHD presentation, and psychotic-like experiences. Multinomial logistic regression suggested that ADHD symptom severity, region, relative age, and stating ADHD medication at three-month follow-up were associated with the response outcome group. However, when validating the data with Bootstrap Forest, none of the variables were significant. Thus, in our large naturalistic cohort, we could not identify any clinically relevant factors that reliably predict pharmacological treatment outcomes. Trial registration: NCT02136147.
Predicting competitive alpine skiing performance by multivariable statistics—the need for individual profiling
Robert Nilsson, Apostolos Theos, Ann-Sofie Lindberg, Christer Malm
Frontiers in Sports and Active Living, 2024
IntroductionPredicting competitive alpine skiing performance using conventional statistical methods has proven challenging. Many studies assessing the relationship between physiological performance and skiing outcomes have employed statistical methods of questionable validity. Furthermore, the reliance on Fédération Internationale de Ski (FIS) points as a performance outcome variable presents additional limitations due to its potential unreliability in reflecting short-term, sport-specific performance. These factors complicate the selection of appropriate tests and the accurate prediction of competitive outcomes.MethodThis study aimed to evaluate the predictive power of a generalized physiological test battery for alpine skiing performance, as measured by FIS points, utilizing multivariable data analysis (MVDA). Physiological test results from a total of twelve (n = 12) world-class female skiers were included in the analysis.ResultsThe result on goodness of regression (R2) and goodness of prediction (Q2) in this study indicate that valid Orthogonal Projection to Latent Structures (OPLS) models for both Slalom and Giant Slalom can be generated (R2 = 0.39 to 0.40, Q2 = 0.21 to 0.15), but also that competition performance still cannot be predicted at a group level (low Q2). In contrast, higher predictive power of competitive performance was achieved on an individual level using the same data (R2 = 0.88 to 0.99 and Q2 = 0.64 to 0.96).DiscussionThe findings of this investigation indicate that the selected tests employed in this study exhibit limited generalizability for the assessment of elite alpine skiers, as the predictive value of specific physiological parameters on competitive performance appears to be highly athlete-dependent.
Darwinian Selection Discriminates Young Athletes: the Relative Age Effect in Relation to Sporting Performance
Johan Jakobsson, A. Lennart Julin, Glenn Persson, Christer Malm
Sports Medicine Open, 2021
Background The relative age effect (RAE) is a worldwide phenomenon, allowing sport participation and elite selection to be based on birthdate distribution. Negative consequences include both a narrow, non-optimal elite selection and negative health effects on entire populations. This study investigated the RAE and athletic performance in multiple individual sports in Sweden. Methods Birthdates of athletes born between the years 1922 and 2015 were collected across 4-month periods (tertiles: T1, T2, T3) from cross-country skiing (N = 136,387), orienteering (N = 41,164), athletics (N = 14,503), alpine skiing (N = 508), E-sports (N = 47,030), and chess (N = 4889). In total, data from 244,560 athletes (women: N = 79,807, men: N = 164,753) was compared to the complete parent population of 5,390,954 births in Sweden during the same years. Chi-squared statistics compared parent and cohort distributions stratified by sport, sex, and age. Results A significantly skewed distribution of birthdates was present in all sports, both sexes, and most age groups. The largest RAEs are seen in children where T1 often constitutes 40–50% and T3, 20–25% of the population. In E-sports, an inversed RAE was seen in adults. In most investigated sports, birthdate distribution was correlated to performance in children but not in adults. Conclusions Skewed birthdate distributions were consistently prevalent in all investigated individual sports in Sweden, both physically demanding and cognitive/skill-based. As sport participation is related to total level of physical activity, both present and future, failing to address the RAE issue at an early age will result not only in a narrow and arbitrary selection for adult elite athletes but also in a negative impact on public health.
Effects of Different Types of Lower Body Resistance Exercise on Upper-body Strength in Men and Women, with Special Reference to Anabolic Hormones
International Journal of Exercise Science, 2021
In vitro phagocytosis of liquid-stored red blood cells requires serum and can be inhibited with fucoidan and dextran sulphate
Andreas Hult, Fredrik Toss, Christer Malm, Per‐Arne Oldenborg
Vox Sanguinis, 2020
Background and ObjectivesRed‐blood‐cells (RBCs) undergo structural and metabolic changes with prolonged storage, which ultimately may decrease their survival after transfusion. Although the storage‐induced damage to RBCs has been rather well described biochemically, little is known about the mechanisms underlying the recognition and rapid clearance of the damaged cells by macrophages.Materials and MethodsWe, here, used a murine model for cold (+4°C) RBC storage and transfusion. Phagocytosis of human or murine RBCs, liquid stored for 6‐8 weeks or 10–14 days, respectively, was investigated in murine peritoneal macrophages.ResultsThe effects of storage on murine RBCs resembled that described for stored human RBCs with regard to decreased adenosine triphosphate (ATP) levels, accumulation of microparticles (MPs) during storage, and RBC recovery kinetics after transfusion. Under serum‐free conditions, phagocytosis of stored human or murine RBCs in vitro was reduced by 70–75%, as compared with that in the presence of heat‐inactivated fetal calf serum (FCS). Human serum promoted phagocytosis of stored human RBCs similar to that seen with FCS. By adding fucoidan or dextran sulphate (blockers of scavenger receptors class A (SR‐A)), phagocytosis of human or murine RBCs was reduced by more than 90%. Phagocytosis of stored human RBCs was also sensitive to inhibition by the phosphatidylinositol 3 kinase‐inhibitor LY294002, the ERK1/2‐inhibitor PD98059, or the p38 MAPK‐inhibitor SB203580.ConclusionRBCs damaged during liquid storage may be recognized by macrophage SR‐A and serum‐dependent mechanisms. This species‐independent recognition mechanism may help to further understand the rapid clearance of stored RBCs shortly after transfusion.
Potential effects of long-term abuse of anabolic androgen steroids on human skeletal muscle
Ji-Guo Yu, Andreas Isaksson, Anton Rova, Yelverton Tegner, Anders Eriksson, et al.
Journal of Sports Medicine and Physical Fitness, 2020
Exercise modulates the levels of growth inhibitor genes before and after multiple sclerosis
Seyed Houtan Shahidi, Mohammad Reza Kordi, Hamid Rajabi, Christer Malm, Farhan Shah, et al.
Journal of Neuroimmunology, 2020
Physical activity and sports—real health benefits: A review with insight into the public health of sweden
Christer Malm, Johan Jakobsson, Andreas Isaksson
Sports, 2019
Positive effects from sports are achieved primarily through physical activity, but secondary effects bring health benefits such as psychosocial and personal development and less alcohol consumption. Negative effects, such as the risk of failure, injuries, eating disorders, and burnout, are also apparent. Because physical activity is increasingly conducted in an organized manner, sport’s role in society has become increasingly important over the years, not only for the individual but also for public health. In this paper, we intend to describe sport’s physiological and psychosocial health benefits, stemming both from physical activity and from sport participation per se. This narrative review summarizes research and presents health-related data from Swedish authorities. It is discussed that our daily lives are becoming less physically active, while organized exercise and training increases. Average energy intake is increasing, creating an energy surplus, and thus, we are seeing an increasing number of people who are overweight, which is a strong contributor to health problems. Physical activity and exercise have significant positive effects in preventing or alleviating mental illness, including depressive symptoms and anxiety- or stress-related disease. In conclusion, sports can be evolving, if personal capacities, social situation, and biological and psychological maturation are taken into account. Evidence suggests a dose–response relationship such that being active, even to a modest level, is superior to being inactive or sedentary. Recommendations for healthy sports are summarized.
Maximal Lactate Steady State and Lactate Thresholds in the Cross-Country Skiing Sub-Technique Double Poling
Johan Jakobsson, Christer Malm
International Journal of Exercise Science, 2019
Physiological Demands of Competitive Sprint and Distance Performance in Elite Female Cross-Country Skiing
Magnus Carlsson, Tomas Carlsson, Lars Wedholm, Mattias Nilsson, Christer Malm, et al.
Journal of Strength and Conditioning Research, 2016
Autologous doping with cryopreserved red blood cells - Effects on physical performance and detection by multivariate statistics
Christer B. Malm, Nelson S. Khoo, Irene Granlund, Emilia Lindstedt, Andreas Hult
Plos One, 2016
Concussed athletes are more prone to injury both before and after their index concussion: A data base analysis of 699 concussed contact sports athletes
Erik Burman, Jack Lysholm, Pashtun Shahim, Christer Malm, Yelverton Tegner
BMJ Open Sport and Exercise Medicine, 2016
Content validity index and intra- and inter- rater reliability of a new muscle strength/ endurance test battery for Swedish soldiers
Helena Larsson, Matthias Tegern, Andreas Monnier, Jörgen Skoglund, Charlotte Helander, et al.
Plos One, 2015
Multivariate statistical assessment of predictors of firefighters' muscular and aerobic work capacity
Ann-Sofie Lindberg, Juha Oksa, Henrik Antti, Christer Malm
Plos One, 2015
High training volumes are associated with a low number of self-reported sick days in elite endurance athletes
Journal of Sports Science and Medicine, 2014
Oxygen uptake at different intensities and sub-techniques predicts sprint performance in elite male cross-country skiers
Magnus Carlsson, Tomas Carlsson, Magnus Knutsson, Christer Malm, Michail Tonkonogi
European Journal of Applied Physiology, 2014
Prediction of race performance of elite cross-country skiers by lean mass
Magnus Carlsson, Tomas Carlsson, Daniel Hammarström, Christer Malm, Michail Tonkonogi
International Journal of Sports Physiology and Performance, 2014
Effects of long term supplementation of anabolic androgen steroids on human skeletal muscle
Ji-Guo Yu, Patrik Bonnerud, Anders Eriksson, Per S. Stål, Yelverton Tegner, et al.
Plos One, 2014
Laboratory or field tests for evaluating firefighters' work capacity?
Ann-Sofie Lindberg, Juha Oksa, Christer Malm
Plos One, 2014
Self-rated physical loads of work tasks among firefighters
Ann-Sofie Lindberg, Christer Malm, Juha Oksa, Désirée Gavhed
International Journal of Occupational Safety and Ergonomics, 2014
Time trials predict the competitive performance capacity of junior cross-country skiers
Magnus Carlsson, Tomas Carlsson, Daniel Hammarström, Christer Malm, Michail Tonkonogi
International Journal of Sports Physiology and Performance, 2014
Scaling maximal oxygen uptake to predict performance in elite-standard men cross-country skiers
Tomas Carlsson, Magnus Carlsson, Majbritt Felleki, Daniel Hammarström, Daniel Heil, et al.
Journal of Sports Sciences, 2013
Field Tests for Evaluating the Aerobic Work Capacity of Firefighters
Ann-Sofie Lindberg, Juha Oksa, Désirée Gavhed, Christer Malm
Plos One, 2013
Scaling of upper-body power output to predict time-trial roller skiing performance
Tomas Carlsson, Magnus Carlsson, Daniel Hammarström, Christer Malm, Michail Tonkonogi
Journal of Sports Sciences, 2013
Transfusion of cryopreserved human red blood cells into healthy humans is associated with rapid extravascular hemolysis without a proinflammatory cytokine response
Andreas Hult, Christer Malm, Per‐Arne Oldenborg
Transfusion, 2013
Exercise-induced muscle damage and inflammation: Re-evaluation by proteomics
Christer Malm, Ji-Guo Yu
Histochemistry and Cell Biology, 2012
Validation of physiological tests in relation to competitive performances in elite male distance cross-country skiing
Magnus Carlsson, Tomas Carlsson, Daniel Hammarström, Toomas Tiivel, Christer Malm, et al.
Journal of Strength and Conditioning Research, 2012
Maximal work capacity and performance depends warm-up procedure and environmental but not inspired air temperatures
Journal of Exercise Physiology Online, 2012
Higher muscle mass but lower gynoid fat mass in athletes using anabolic androgenic steroids
Anna Nordström, Gabriel Högström, Anders Eriksson, Patrik Bonnerud, Yelverton Tegner, et al.
Journal of Strength and Conditioning Research, 2012
Immunological alterations used to predict infections in response to strenuous physical training
Örjan Ekblom, Björn Ekblom, Christer Malm
Military Medicine, 2011
Protein differences between human trapezius and vastus lateralis muscles determined with a proteomic approach
Jenny Hadrévi, Fredrik Hellström, Thomas Kieselbach, Christer Malm, Fatima Pedrosa-Domellöf
BMC Musculoskeletal Disorders, 2011
Effect of local leg cooling on upper limb trajectories and muscle function and whole body dynamic balance
Hugo Piedrahita, Juha Oksa, Hannu Rintamäki, Christer Malm
European Journal of Applied Physiology, 2009
Evaluation of 2-D DIGE for skeletal muscle: Protocol and repeatability
Christer Malm, Jenny Hadrevi, Sven‐Anders Bergström, Fatima Pedrosa‐Domellöf, Henrik Antti, et al.
Scandinavian Journal of Clinical and Laboratory Investigation, 2008
Health problems related to working in extreme cold conditions indoors
Hugo Piedrahita, Juha Oksa, Christer Malm, Hannu Rintamäki
International Journal of Circumpolar Health, 2008
Effects of cooling and clothing on vertical trajectories of the upper arm and muscle functions during repetitive light work
Hugo Piedrahita, Juha Oksa, Christer Malm, Erja Sormunen, Hannu Rintamäki
European Journal of Applied Physiology, 2008
Infectious episodes before and after a marathon race
B. Ekblom, Ö. Ekblom, C. Malm
Scandinavian Journal of Medicine and Science in Sports, 2006
Susceptibility to infections in elite athletes: The S-curve
C. Malm
Scandinavian Journal of Medicine and Science in Sports, 2006
Skeletal muscle morphology in power-lifters with and without anabolic steroids
Anders Eriksson, Fawzi Kadi, Christer Malm, Lars-Eric Thornell
Histochemistry and Cell Biology, 2005
Physical activity both enhances and depresses the immune system
Lakartidningen, 2005
Exercise immunology: The current state of man and mouse
Christer Malm
Sports Medicine, 2004
Immune system alteration in response to increased physical training during a five day soccer training camp
C. Malm, Ö. Ekblom, B. Ekblom
International Journal of Sports Medicine, 2004
Leukocytes, cytokines, growth factors and hormones in human skeletal muscle and blood after uphill or downhill running
Christer Malm, Bertil Sjödin, Berit Sjöberg, Rodica Lenkei, Per Renström, et al.
Journal of Physiology, 2004
Immune system alteration in response to two consecutive soccer games
C. Malm, Ö. Ekblom, B. Ekblom
Acta Physiologica Scandinavica, 2004
Exercise immunology: A skeletal muscle perspective
Exercise Immunology Review, 2002
Eccentric contractions leading to DOMS do not cause loss of desmin nor fibre necrosis in human muscle
Ji-Guo Yu, Christer Malm, Lars-Eric Thornell
Histochemistry and Cell Biology, 2002
Exercise-induced muscle damage and inflammation: Fact or fiction?
C. Malm
Acta Physiologica Scandinavica, 2001
Effect of eccentric exercise on muscle oxidative metabolism in humans
BRANDON WALSH, MICHAIL TONKONOGI, CHRISTER MALM, BJ??RN EKBLOM, KENT SAHLIN
Medicine and Science in Sports and Exercise, 2001
Immunological changes in human skeletal muscle and blood after eccentric exercise and multiple biopsies
Christer Malm, Pernilla Nyberg, Marianne Engström, Bertil Sjödin, Rodica Lenkei, et al.
Journal of Physiology, 2000
Effects of ubiquinone-10 supplementation on physical performance in humans
Coenzyme Q Molecular Mechanisms in Health and Disease, 2000
Effects of eccentric exercise on the immune system in men
Christer Malm, Rodica Lenkei, Bertil Sjödin
Journal of Applied Physiology, 1999
Effect of Q10 supplementation on tissue Q10 levels and adenine nucleotide catabolism during high-intensity exercise
Michael Svensson, Christer Malm, Michail Tonkonogi, Bjǒrn Ekblom, Bertil Sjödin, et al.
International Journal of Sport Nutrition, 1999
Effects of ubiquinone-10 supplementation and high intensity training on physical performance in humans
C. MALM, M. SVENSSON, B. EKBLOM, B. SJÖDIN
Acta Physiologica Scandinavica, 1997
Supplementation with ubiquinone-10 causes cellular damage during intense exercise
C. MALM, M. SVENSSON, B. SJÖBERG, B. EKBLOM, B. SJÖDIN
Acta Physiologica Scandinavica, 1996

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