Per A Tesch

• PhD
• Principal Investigator at Karolinska Institutet

In the current study, we compared muscle morphology in three advanced aging cohorts that differed in physical function, including a unique cohort of lifelong endurance athletes. Biopsies from the vastus lateralis muscle of seven lifelong endurance athletes (EA) aged 82-92 years, and nineteen subjects from the Uppsala Longitudinal Study of Adult Men...

The current study explored whether the marked hypertrophic response noted with a short-term unilateral concurrent exercise paradigm was associated with more prominent changes in myonuclei accretion, ribosome biogenesis and capillarization compared to resistance exercise alone (RE). Ten men (age 25±4yr) performed aerobic and resistance exercise (AE+...

This study explored the muscle genome‐wide response to long‐term unloading (84‐day bed rest) in 21 men. We hypothesized that a part of the bed rest‐induced gene expression signature would be resilient to a concurrent flywheel resistance exercise (RE) countermeasure. Using DNA microarray technology analyzing 35 345 gene‐level probe‐sets, we identifi...

As manual immunohistochemical analysis of features such as skeletal muscle fiber typing, capillaries, myonuclei and fiber-size related parameters is time-consuming and prone to user subjectivity, automatic computational methods could allow for faster and more objective evaluation. Here, we developed Muscle2View, a free CellProfiler-based pipeline t...

In the quest for a viable non-gravity dependent method to “lift weights” in space, our laboratory introduced iso-inertial resistance (YoYo™) exercise using spinning flywheel(s), more than 25 years ago. After being thoroughly tested in individuals subjected to various established spaceflight analogs, a multi-mode YoYo™ exercise apparatus was eventua...

As metabolic changes in human skeletal muscle after long-term (simulated) spaceflight are not well understood, this study examined the effects of long-term microgravity, with and without concurrent resistance exercise on skeletal muscle oxidative and glycolytic capacity. Twenty-one men were subjected to 84 days head-down tilt bed rest with (BRE; n=...

The present study examined site-specific hamstring muscles use with functional magnetic resonance imaging (MRI) in elite soccer players during strength training. Thirty-six players were randomized into four groups, each performing either Nordic hamstring, flywheel leg-curl, Russian belt or the hip-extension conic-pulley exercise. The transverse rel...

Introduction Maximal Voluntary isometric Contraction force (MVC) is considered as one of the best tools for quantifying muscle damage (Raastad et al. 2010). Other performance related to muscle function, such as jump performance, has been reported to be affected by Exercise Induced Muscle Damage (EIMD). The aim of this study was to assess which para...

Introduction: This study examined the effects of long-term bed rest with or without a concurrent resistance exercise protocol on different muscle function indices of the knee extensors and their influence on previously shown atrophy, neural impairment, and slow-to-fast phenotype shift. Methods: Nine men underwent 90 d of bed rest only (BR), whil...

This study used functional magnetic resonance imaging (fMRI) to compare individual muscle use in exercises aimed at preventing hamstring injuries. Thirty-six professional soccer players were randomized into 4 groups, each performing either Nordic hamstring, flywheel leg curl, Russian belt or conic-pulley exercise. MRIs were performed before and imm...

Recent reports suggest that aerobic exercise may boost the hypertrophic response to short-term resistance training. This study explored the effects of an acute aerobic exercise bout on the transcriptional response to subsequent resistance exercise. Ten moderately trained men performed ~45 min cycling on one leg followed by 4x7 maximal knee extensio...

Background Resistance exercise (RE) improves neuromuscular function and physical performance after stroke. Yet, the effects of RE emphasizing eccentric (ECC; lengthening) actions on muscle hypertrophy and cognitive function in stroke patients are currently unknown. Thus, this study explored the effects of ECC-overload RE training on skeletal muscle...

The unilateral lower limb suspension (ULLS) method was developed, introduced and validated in the quest for a simple, effective and highly reliable human analogue to study the consequences of spaceflight on muscle size and function. As withdrawal of weight bearing for no more than 2-3 days is sufficient to inflict disturbances in protein metabolism...

Background: Although several exercise systems have been developed to mitigate the physiological deconditioning that occurs in microgravity, few have the capacity to positively impact multiple physiological systems and still meet the volume/mass requirements needed for missions beyond low Earth orbit. The purpose of this study was to test the gravi...

Volley- and basketball players can be considered as a population at risk for patellar tendinopathy. Given the paradox that eccentric training elicits therapeutic benefits yet might provoke such injury, we investigated the influence of a weekly bout of inertial squat resistance exercise offering eccentric overload on lower limb muscle power and pate...

Purpose: The objective of this study is to examine the effect of a high-intensity concurrent training program using a single gravity-independent device on maintaining skeletal muscle function and aerobic capacity during short-term unilateral lower limb suspension (ULLS). Methods: Nineteen subjects (10 males and 9 females; 21.0 ± 2.5 yr, 65.4 ± 12....

This study examined the effects of a novel iso-inertial eccentric overload and vibration training (EVT) paradigm on change of direction speed and multiple performance tests applicable to soccer. Twenty-four young, male players were assigned to EVT (n=12) or conventional combined (CONV, n=12) group, once weekly for 11 weeks. EVT consisted of 2 sets...

General health, sporting requirements, and environments, e.g. space flight, that warrant the need for cardiovascular and musculoskeletal maintenance often incorporate both aerobic (AE) and resistance exercise (RE) training. Concurrent training has shown potential interference effects and therefore it is important to examine whether there are sex di...

Background Resistance exercise comprising eccentric (ECC) muscle actions enhances muscle strength and function to aid stroke patients in conducting daily tasks. The purpose of this study was to assess the efficacy of a novel ECC-overload flywheel resistance exercise paradigm to induce muscle and functional performance adaptations in chronic stroke...

We hypothesised that load-sensitive expression of costameric proteins, which hold the sarcomere in place and position the mitochondria, contributes to the early adaptations of antigravity muscle to unloading and would depend on muscle fibre composition and chymotrypsin activity of the proteasome. Biopsies were obtained from vastus lateralis (VL) an...

Background: As spaceflight compromises skeletal muscle oxidative and aerobic work capacity, this study assessed the efficacy of resistance exercise (RE) to counteract muscle metabolic perturbations induced by 5 wk unilateral lower limb unloading (UL). Methods: There were 21 men and women (30-56 yr) who were randomly assigned to either UL with (G...

AimA truncated PGC-1α splice variant (PGC-1α4) has been implicated in the regulation of resistance-exercise (RE) induced muscle hypertrophy, and basal expression levels said to be augmented in response to concurrent aerobic (AE) and RE training.The current study investigated human muscle truncated and non-truncated PGC-1α transcripts in response to...

As aerobic exercise (AE) may interfere with adaptations to resistance exercise (RE), this study explored acute and chronic responses to consecutive AE (~45 min cycling) and RE (4 x 7 maximal knee extensions), vs. RE only. Ten men performed acute unilateral AE+RE interspersed by 15 min recovery. The contralateral leg was subjected to RE. This exerci...

This study assessed and compared acute muscle molecular responses before and after 5 wks training, employing either aerobic (AE) and resistance exercise (RE) or RE only. Ten men performed one-legged RE, while the contralateral limb performed AE followed by RE 6 h later (AE+RE). Before (untrained) and after (trained) the intervention, acute bouts of...

General health, sporting requirements, and environments, e.g. space flight, that warrant the need for cardiovascular and musculoskeletal maintenance often incorporate both aerobic (AE) and resistance exercise (RE) training. Concurrent training has shown potential interference effects and therefore it is important to examine whether there are sex di...

PURPOSE: Master athletes (>80 y) who have vigorously exercised their entire adult lives represent a unique and expanding demographic of the aging population, providing an opportunity to gain insights into the potential health benefits of lifelong exercise. The aim of this investigation was to characterize slow (MHC I) and fast (MHC IIa) single musc...

PURPOSE: To date, little is known about the potential benefits of lifelong endurance exercise on skeletal muscle health. Therefore, the purpose of this investigation was to characterize skeletal muscle of elite lifelong endurance athletes (n=9, 81±1 y, VO2max=38±1 ml·kg-1·min-1) and age-matched, healthy, untrained men (n=6, 82±1 y, VO2max=21±1 ml·k...

Astronauts are required to perform both resistance and aerobic exercise while in orbit. This study assessed the aerobic energy yield and related physiological measurements using a nongravity dependent flywheel device designed for both resistance and aerobic exercise (RAD) in space. Eight physically active men and women performed all-out rowing on t...

to the editor: Drs. Lepers and colleagues ([1][1]) have written an interesting commentary in response to our recently published paper ([2][2]) on aerobic power in octogenarian athletes and healthy untrained age-matched men. Our primary intent was to evaluate aerobic potential at the whole body and

This study tested the hypothesis that chronic aerobic and resistance exercise (AE+RE) would elicit greater muscle hypertrophy than resistance exercise only (RE). Ten men (25±4 yrs) performed 5 wks unilateral knee extensor AE+RE. The opposing limb was subjected to RE. AE completed 6 hrs prior to RE, consisted of ~45 min one-legged cycle ergometry. R...

We examined whole body aerobic capacity and myocellular markers of oxidative metabolism in lifelong endurance athletes (n=9, 81±1 y, 68±3 kg, BMI=23±1 kg/m(2)) and age-matched, healthy, untrained men (n=6; 82±1 y, 77±5 kg, BMI=26±1 kg/m(2)). The endurance athletes were cross-country skiers, including a former Olympic champion and several national/r...

The unilateral lower limb suspension (ULLS) model is used to study disuse conditions, such as spaceflight, which typically induce a slow-to-fast phenotype transition. The vastus lateralis (VL) and soleus (SOL) are both antigravity muscles that are very sensitive to changes in loading states. We investigated whether fiber type changes associated wit...

The unilateral lower limb suspension (ULLS) model is used to study disuse conditions, such as spaceflight, which typically induce a slow‐to‐fast phenotype transition. The vastus lateralis (VL) and soleus (SOL) are both antigravity muscles that are very sensitive to changes in loading states. We investigated whether fiber type changes associated wit...

This study assessed the influence of an acute aerobic exercise bout on molecular responses to subsequent resistance exercise (RE). Nine physically active men performed a 45-min one-legged cycle ergometry exercise and 4 × 7 maximal concentric-eccentric knee extensions for each leg 6 h later. Thus, one limb was subjected to aerobic and resistance exe...

An increased prevalence of myosin heavy chain (MHC) hybrid muscle fibers (MHC I/IIa, IIax, and/or I/IIax) and the MHC IIx isoform is associated with elderly, sedentary, spinal cord injured, and bed ridden populations. Accordingly, highly trained young athletes typically express few MHC hybrid fibers and little MHC IIx isoform. To date there is no d...

Long-term residence in microgravity induces muscle atrophy, which leads to reduction in aerobic fitness and muscle strength. We tested the efficacy of a new flywheel exercise trainer on a group of young sedentary subjects (16 men, 16 women). Subjects were assigned to either resistance-only (RE) or combined aerobic/resistance (AE/RE) cohort for 5 we...

Case-series study with pre- vs. post-test measurements design. Strength training programs emphasizing eccentric muscle actions have received much attention in the treatment of tendinopathies. The current study reports on the efficacy of a novel strength training paradigm using inertial eccentric-concentric resistance to treat chronic patellar tendi...

Resistance exercise has been proposed as an aid to counteract quadriceps muscle atrophy in astronauts during extended missions in orbit. While space authorities have advocated the squat exercise should be prescribed, no exercise system suitable for in-flight use has been validated with regard to quadriceps muscle use. We compared muscle involvement...

Changes in muscle activation and performance were studied in healthy men in response to 5 weeks of resistance training with or without "eccentric overload". Subjects, assigned to either weight stack (grp WS; n = 8) or iso-inertial "eccentric overload" flywheel (grp FW; n = 9) knee extensor resistance training, completed 12 sessions of four sets of...

Changes in skeletal muscle mass are controlled by mechanisms that dictate protein synthesis or degradation. The current human study explored whether changes in activation of the phosphoinositide 3-kinase (PI3K)-Akt1, p38, myostatin, and mRNA expression of markers of protein degradation and synthesis occur soon after withdrawal of weight bearing. Bi...

Abstract: PURPOSE: To examine whole body aerobic capacity and myocellular markers of oxidative capacity in lifelong endurance athletes (n=9, 81±1 y, 68±3 kg, BMI=23±1 kg/m2) and compare to age-matched, independent living, healthy men (n=6; 82±1 y, 77±5 kg, BMI=26±1 kg/m2). The endurance athletes were cross-country skiers, including a former Olympic...

Alpha-actinins are structural proteins of the Z-line. Human skeletal muscle expresses two alpha-actinin isoforms, alpha-actinin-2 and alpha-actinin-3, encoded by their respective genes ACTN2 and ACTN3. ACTN2 is expressed in all muscle fiber types, while only type II fibers, and particularly the type IIb fibers, express ACTN3. ACTN3 (R577X) polymorp...

to the editor: Several points need to be made to allow the readers of the Journal of Applied Physiology to put the comments made by Drs. Rennie, Phillips, and Smith ([3][1]) into proper context. 1 ) We will begin by addressing the two specific points raised about methodology. First, the authors of

Skeletal muscle atrophy is evident after muscle disuse, unloading, or spaceflight and results from decreased protein content as a consequence of decreased protein synthesis, increased protein breakdown or both. At this time, there are essentially no human data describing proteolysis in skeletal muscle undergoing atrophy on Earth or in space, primar...

Any change in skeletal muscle mass is controlled by the balance of protein synthesis and degradation. These processes require signalling through the PI3K‐Akt‐mTOR and ubiquitin‐proteasome pathways. This study explored whether these pathways are activated soon after withdrawal of weight bearing. Muscle biopsies were obtained from m. vastus lateralis...

The flywheel exercise device (FWED) is planned for use as an in-flight exercise system, to demonstrate its efficacy as a countermeasure device to prevent muscle atrophy, bone loss and impairment of muscle function in human beings in response to long duration spaceflight. It is intended to be used on the International Space Station (ISS) and will be...

Fifteen healthy men performed a 5-week training program comprising four sets of seven unilateral, coupled concentric-eccentric knee extensions 2-3 times weekly. While eight men were assigned to training using a weight stack (WS) machine, seven men trained using a flywheel (FW) device, which inherently provides variable resistance and allows for ecc...

Acute adaptations to strength exerciseChronic adaptations to strength exerciseConclusions References

Mutations in PINK1 cause the mitochondrial-related neurodegenerative disease Parkinson's. Here we investigate whether obesity, type 2 diabetes, or inactivity alters transcription from the PINK1 locus. We utilized a cDNA-array and quantitative real-time PCR for gene expression analysis of muscle from healthy volunteers following physical inactivity,...

We examined the effects of 35 and 90 days of simulated microgravity with or without resistance-exercise (RE) countermeasures on the content of the general skeletal muscle protein fractions (mixed, sarcoplasmic, and myofibrillar) and specific proteins that are critical for muscle function (myosin, actin, and collagen). Subjects from two studies, usi...

Body fluid redistribution occurs in astronauts traveling in space, potentially altering interstitial water content and hence impedance. This in turn may impact the features of electromyographic (EMG) signals measured to compare in-flight muscle function with pre- and post-flight conditions. Thus, the current study aimed at investigating the influen...

A gravity-independent flywheel exercise device (FWED) has been proven effective as a countermeasure to loss of strength and muscle atrophy induced by simulated microgravity. This study assessed muscle-fiber conduction velocity (CV) and surface EMG instantaneous mean power spectral frequency (iMNF) during brief bouts of fatiguing concentric (CON) an...

Recent studies have implicated the mTOR-signaling pathway as a primary component for muscle growth in mammals. The purpose of this investigation was to examine signaling pathways for muscle protein synthesis after resistance exercise. Sprague-Dawley rats (male, 6 mo old) were assigned to either resistance exercise or control groups. Resistance exer...

Physical activity enhances muscle mitochondrial gene expression, while inactivity and mitochondrial dysfunction are both risk factors for developing diabetes. Defective activation of the transcriptional coactivator PGC-1alpha may contribute to the gene expression pattern observed in diabetic and insulin-resistant skeletal muscle. We proposed that g...

This investigation determined the effects of 84 days of bedrest on the composition of myosin heavy chain (MHC) in single skeletal muscle fibres with and without a resistance-training countermeasure programme. Muscle biopsies were obtained from the m. vastus lateralis (VL) and m. soleus (SOL) before and after 84 days of bedrest. While control (BR) s...

Exercise-induced shifts in signal intensity (SI) of magnetic resonance (MR) images were examined to assess indirectly muscle use in closed- and open-chain knee extensor exercises. Eight men performed five sets of 8-12 repetitions in the leg press (LP) and the seated knee extension (KE) exercises at 50, 75 and 100%, respectively of the 5 x 10 repeti...

Muscle atrophy and bone loss pose substantial problems for long-term space flight and in clinical immobilization. We therefore tested the efficacy of flywheel resistive exercise and pamidronate to counteract such losses. Twenty five young healthy males underwent strict bed rest with -6 degrees head-down tilt for 90 days. Subjects were randomized in...

The Topical Team for Muscle Physiology has identified and discussed the basic parameters and functions in relation to the change of loading and activity pattern seen during simulated and actual spaceflight. A significant overlap with similar situations on Earth can be identified, with clinical application as a direct benefit. It is pointed that hum...

It is generally held that space travelers experience muscle dysfunction and atrophy during exposure to microgravity. However, observations are scarce and reports somewhat inconsistent with regard to the time course, specificity and magnitude of such changes. Hence, we examined four male astronauts (group mean approximately 43 years, 86 kg and 183 c...

Skeletal muscle atrophy and strength loss induced by short-term simulated spaceflight are offset or attenuated by resistance exercise (RE). This study compared the effects of plantar flexor and knee extensor RE on muscle size and function in 17 healthy men (aged 26-41years) subjected to 90 days 6 degrees head-down-tilt bed rest with (BRE; n = 8) or...

Previously, it has been shown that the human ground-based model consisting of unilateral limb suspension (ULLS) induces atrophy and reduced strength of the affected quadriceps muscle group. Resistance exercise (RE) involving concentric-eccentric actions, in the face of ULLS, is effective in ameliorating these deficits. The goal of the present study...

Hindlimb suspension (HS) results in rapid losses of muscle mass, which may in part be explained by attenuated rates of protein synthesis. Mammalian target of rapamycin (mTOR) regulates protein synthesis and has been implicated as a potential mediator of the muscle mass decrement with HS. This study examined the effect of resistance exercise, a musc...

It is generally believed the calf muscles in humans are relatively unresponsive to resistance training when compared with other muscles of the body. The purpose of this investigation was to determine the muscle protein synthesis response of the soleus muscle following a standard high intensity bout of resistance exercise. Eight recreationally activ...

Adaptive changes of major body systems in astronauts during spaceflight can be simulated by strict anti-orthostatic head-down tilt (HDT) bed rest (BR), a ground-based microgravity (microG) model that provides a meaningful opportunity to study atrophy mechanisms and possible countermeasures under controlled experimental conditions. As nitric oxide (...

This study determined changes in knee extensor and plantar flexor muscle volume during 29 days of bed rest with or without resistance exercise using a gravity-independent flywheel ergometer. Seventeen men (26-41 years) were subjected to 29 days of bed rest with (n = 8) or without (n = 9) resistance exercise; Supine Squat (SS) and Calf Press (CP) pe...

Muscle biopsies were obtained from the vastus lateralis before and after 84 days of bed-rest from six control (BR) and six resistance-exercised (BRE) men to examine slow- and fast-twitch muscle fibre contractile function. BR did not exercise during bed-rest and had a 17 and 40% decrease in whole muscle size and function, respectively. The BRE group...

In an effort to simulate the compromised function and atrophy of lower limb muscles experienced by astronauts after spaceflight, 21 men and women age 30-56 yr were subjected to unilateral lower limb unloading for 5 wk. Whereas 10 of these subjects performed unilateral knee extensor resistance exercise (ULRE) two or three times weekly, 11 subjects (...

The efficacy of a mechanical, gravity-independent resistance exercise (RE) system to induce strength gains and muscle hypertrophy was validated. Designed for space crew in orbit, this technique offers resistance during coupled concentric and eccentric actions by utilizing the inertia of a rotating flywheel(s), set in motion by the trainee. Ten midd...

The efficacy of a resistance exercise paradigm, using a gravity-independent flywheel principle, was examined in four men subjected to 110 days of confinement (simulation of flight of international crew on space station; SFINCSS-99). Subjects performed six upper- and lower-body exercises (calf raise, squat, back extension, seated row, lateral should...

Atrophy of skeletal muscle is observed in response to immobilization and lack of weight-bearing. The aim of this study was to investigate the effect of immobilization on muscle protein synthesis and associated biochemical parameters in skeletal muscle of healthy volunteers employing a standardized model of lower limb unloading. One leg was unloaded...

Exposure to microgravity and/or spaceflight causes dramatic losses in both muscle and bone mass. In normal gravity, resistance exercise has been effectively used to increase muscle and bone mass. We tested a novel form of resistance exercise training using flywheel technology as a countermeasure to offset the loss of musculoskeletal mass during 4 w...

The effects of 5 weeks of unilateral lower limb suspension (ULLS) and flywheel resistance exercise (RE) on skeletal muscle protein composition were examined in thirty-one subjects (40 +/- 8y), divided into three groups: ULLS, ULLS+RE, and RE. Pre and post biopsy samples were examined for protein concentration, myosin heavy chain (MHC) and actin con...

We examined the distribution of the myosin heavy chain (MHC) isoforms (I, IIa, IIx) of the leg muscles of three groups of men and women (40 +/- 8y) that completed unilateral lower limb suspension only (ULLS), ULLS plus resistance exercise (ULLS+RE), or RE only (RE) for 5 weeks. Muscle biopsies were obtained pre and post from the vastus lateralis of...

The effects of resistance training with concentric or concentric-eccentric muscle actions on the acute hormonal response to a resistance exercise protocol was investigated. Thirty-two men completed a 19 week lower-body resistance training program (consisting of the leg press and leg extension exercises) in which they (1) performed concentric action...

This study investigated whether hyperbaric oxygen therapy (HBOT) improves recovery after exercise-induced muscle injury. Healthy male subjects (N = 24) were randomly assigned to either a placebo group or a HBOT group. Subjects were tested for maximal isometric strength (preexercise) of their right elbow flexors. Each subject then completed a high-f...