Everyday function in schizophrenia: The impact of aerobic endurance and skeletal muscle strength.

BACKGROUND: Patients with schizophrenia suffer from physical health conditions, culminating in reduced physical functioning with enormous costs for patients and society. Although aerobic endurance and skeletal muscle strength, typically reduced in this population, relate to cognition and function, no study has explored their respective contributions to performance of functional skills and everyday tasks. METHODS: In a cross-sectional study, 48 outpatients (28/20 men/women; 35 ± 11(SD) years) with schizophrenia spectrum disorders (ICD-10; F20-25) were administered the UCSD Performance-based Skills Assessment-Brief (UPSA-B; functional skills), Specific Level of Functioning (SLOF; functional performance) and the Positive and Negative Syndrome (PANSS) scale. Peak oxygen uptake (V̇O2peak) was assessed along with leg press maximal muscle strength (1RM) and mechanical power. RESULTS: UPSA-B performance was associated with V̇O2peak (r = 0.28,p < 0.05), accounting for 8 % (p < 0.05) of shared variance, but was unrelated to 1RM and mechanical power. The SLOF physical functioning domain was associated with V̇O2peak (r = 0.30,p < 0.05) and 1RM (r = 0.24,p < 0.05), while SLOF personal care (r = 0.27,p < 0.05) and activities (r = 0.30,p < 0.05) were related only to V̇O2peak. Hierarchical regression analyses revealed that while V̇O2peak and age combined to account for 20 % (p < 0.05) of the variance in physical functioning, the contribution of 1RM was eliminated after adjusting for age. V̇O2peak and negative symptoms combined predicted 24 % and 35 % of the variance in personal care and activities, respectively. UPSA-B scores did not add to the prediction of SLOF scores. CONCLUSIONS: Although V̇O2peak and 1RM both relate to functional outcomes, the combination of V̇O2peak, age, and negative symptoms exert the greatest detrimental influence on functional performance beyond skills deficits.

Strength training integrated in long term collaborative care of patients with schizophrenia.

INTRODUCTION: Skeletal muscle strength is reduced in patients with schizophrenia, contributing to their impaired physical health, functional performance, and potentially mental health challenges. Although short-term training programs have shown promising results, improving muscle strength and functional performance, it is unknown how exercise can be successfully integrated into the long-term clinical care of outpatients with schizophrenia. OBJECTIVE: To investigate effects of strength training with adherence support in a collaborative care model. METHODS: We randomized 28 men and 20 women (mean ± SD, 35 ± 11 years) to leg press maximal strength training (MST) with 4 sets at 90 % of one repetition maximum (1RM) 2 × week, facilitated by municipal service and professional supervision (TG), or a control group (CG). RESULTS: The TG increased scaled leg press 1RM (0-3 months: 19 %; 0-6 months: 31 %, 0-12 months: 40 %, all p < .001, and 3-12 months: 18 %, p < .05) and power (0-3 months, 11 %; 0-6 months: 22 %, 0-12 months: 26 %, all p < .001, and 3-12 months: 13 %, p < .05) throughout the 1-year period compared to the CG. The increased muscle strength was accompanied by improved sit-to-stand performance (20 %) after 12 months (p < .001). Both groups also exhibited within-group improvements in walking work efficiency after 6 months (TG: 13 %; CG: 23 %) and 1 year (TG: 11 %; CG: 21 %, p < .01-0.05), but with no evident differences between the groups. Stair climbing performance remained unchanged. CONCLUSION: Our results reveal that strength training can successfully be integrated as a part of long-term clinical care of outpatients with schizophrenia, contributing to improved functional performance.

Physical Health Impairment and Exercise as Medicine in Severe Mental Disorders: A Narrative Review.

BACKGROUND: Individuals with severe mental disorders (SMDs; schizophrenia spectrum disorders, bipolar disorder, and major depressive disorder) are not only suffering from their mental conditions; they also have an attenuated physical health, augmenting their overall critical condition. OBJECTIVES: We review and critically appraise the evidence based on (1) key physiological factors relating to aerobic endurance and skeletal muscle strength; (2) implications for physical function and health; and (3) effects of training interventions with different intensities evaluated in individuals with SMDs. FINDINGS: Reductions in aerobic endurance factors, peak oxygen uptake (VO2peak) and walking work efficiency, are paralleled by reductions in maximal skeletal muscle strength and power. In turn, the poor aerobic endurance and muscle strength lead to impaired physical function, increased risk of lifestyle-related diseases, and ultimately early death. Exercise has the potential to counteract the attenuated physical health in people with SMDs. While aerobic endurance training is shown to increase VO2peak due to plasticity of the oxygen transport system, strength training is documented to improve maximal muscle strength, power, and walking work efficiency as a result of adaptations in neuromuscular force developing factors. CONCLUSIONS: In conclusion, improvements in these key determinants for physical health appear to be achievable in people with SMDs despite many being challenged by motivational difficulties with attending regular exercise and have beneficial implications for physical function during activities of daily living, lifestyle-related diseases, and early death.

Test-Retest Reliability of the Patient Activation Measure-13 in Adults with Substance Use Disorders and Schizophrenia Spectrum Disorders.

Patient Activation Measure-13 (PAM-13) is a valid and widely used questionnaire that assess an individual's knowledge, confidence, and skills for self-management of their chronic illness. Although there is some evidence regarding its reliability, the test-retest reliability has not been investigated among patients with substance use disorders (SUDs) or schizophrenia spectrum disorders. We investigated the internal consistency and test-retest reliability of PAM-13 in these populations. Test-retest reliability was analysed using data from 29 patients with SUDs and 28 with schizophrenia spectrum disorders. Cronbach's α and Intraclass Correlation Coefficient (ICC) scores were used to examine internal consistency and test-retest reliability, respectively. Of the 60 collected test-retest questionnaires, 57 were included in the analyses. No mean differences between time one (T1) and time two (T2) were observed in either patient group, except for item 12 in schizophrenia spectrum disorders patients (p < 0.05). Internal consistency for T1 and T2 was 0.75 and 0.84 in SUDs patients and 0.87 and 0.81 in schizophrenia spectrum disorders patients, respectively. The ICC was r = 0.86 in patients with SUDs and r = 0.93 in patients with schizophrenia spectrum disorders. To conclude, PAM-13 showed good internal consistency and test-retest reliability in SUDs and schizophrenia spectrum disorders patients.

Strength training restores force-generating capacity in patients with schizophrenia.

Patients with schizophrenia spectrum disorders have impaired skeletal muscle force-generating capacity (FGC) of the lower extremities, that is, one repetition maximum (1RM) and rapid force development, and poor functional performance. We therefore investigated whether 12 weeks of maximal strength training (MST) could (a) restore FGC and functional performance to the level of healthy references, (b) increase patient activation and quality of life, and (c) explore associations between symptom severity, defined daily dose of medication, illness duration, level of patient activation, and improvements in FGC and functional performance. Forty-eight outpatients were randomized to a training group (TG) or control group (CG). TG performed leg press MST 2 day/week at ~ 90% 1RM. The CG received two introductory training sessions and encouragement to train independently. Leg press 1RM, rapid force development, a battery of functional performance tests, Patient Activation Measure-13, and 36-Item Short Form Health Survey were tested. Healthy references performed baseline tests of FGC and functional performance. Thirty-six patients completed the study (TG: 17, CG: 19). TG improved 1RM (28%) and rapid force development (20%, both P < .01) to a level similar to healthy references, while no change was apparent in the CG. TG's improvement in rapid force development was negatively associated with defined daily dose of medication (r = -0.5, P = .05). Both TG and CG improved 30-second sit-to-stand test performance (P < .05) which was associated with improved rapid force development (r = 0.6, P < .05). In conclusion, 12 weeks of MST restored patients' lower extremity FGC to a level similar to healthy references and improved 30-second sit-to-stand test performance.

One-year aerobic interval training in outpatients with schizophrenia: A randomized controlled trial.

Although aerobic interval training (AIT) is recognized to attenuate the risk of cardiovascular disease (CVD) and premature mortality, it appears that it rarely arrives at patients' doorsteps. Thus, this study investigated 1-year effects and feasibility of AIT delivered with adherence support in collaborative care of outpatients with schizophrenia. Forty-eight outpatients (28 men, 35 [31-38] (mean [95% confidence intervals]) years; 20 women, 36 [30-41] years) with schizophrenia spectrum disorders (ICD-10) were randomized to either a collaborative care group provided with municipal transportation service and training supervision (walking/running 4 × 4 minutes at ~90% of peak heart rate; HRpeak ) 2 d wk-1 at the clinic (TG) or a control group (CG) given 2 introductory AIT sessions and advised to continue training. Directly assessed peak oxygen uptake ( V ˙ O 2 peak ) increased in the TG after 3 months (2.3 [0.6-4.4] mL kg-1  min-1 , Cohen's d = 0.33[-4.63 to 4.30], P = 0.04), 6 months (2.7 [0.5-4.8] mL kg-1  min-1 , Cohen's d = 0.42[-4.73 to 4.11], P = 0.02) and 1 year (4.6 [2.3-6.8] mL kg-1  min-1 , Cohen's d = 0.70[-4.31 to 4.10], P < 0.001) compared to the CG. One-year cardiac effects revealed higher HRpeak (7 [2-11] b min-1 , Cohen's d = 0.34[-8.48 to 8.65], P = 0.01), while peak stroke volume tended to be higher (0.9 [-0.2 to 2.0] mL b-1 , Cohen's d = 0.35[-1.62 to 2.01], P = 0.11) in the TG compared to the CG. Conventional risk factors (body weight, waist circumference, blood pressure, and lipids/glucose) remained unaltered in both groups. One-year AIT adherence rates were 15/25 (TG; different from CG: P < 0.001) and 0/23 (CG). AIT was successfully included in long-term collaborative care of outpatients with schizophrenia and yielded improved V ˙ O 2 peak , advocating this model for aerobic capacity improvement and CVD risk reduction in future treatment.

Patients with schizophrenia have impaired muscle force-generating capacity and functional performance.

Patients with schizophrenia have impaired physical health. However, evidence of how skeletal muscle force-generating capacity (FGC), a key component of functional performance, may contribute to the impairment is scarce. Thus, the aim of this study was to investigate the patient groups' skeletal muscle FGC and its association with functional performance. Leg-press FGC was assessed along with a battery of functional performance tests in 48 outpatients (28 men, 34 ± 10 years; 20 women, 36 ± 12 years) with schizophrenia spectrum disorder (ICD-10, F20-29), and compared with 48 healthy age- and gender-matched references. Results revealed reduced one-repetition maximum (1RM) in men (-19%, P < .01) and a trend toward reduction in women (-13%, P = .067). The ability to develop force rapidly was also impaired (men: -30%; women: -25%, both P < .01). Patients scored worse than healthy references on all physical performance tests (stair climbing: -63%; 30-second sit-to-stand (30sSTS): -48%; six-minute walk test (6MWT): -22%; walking efficiency: -14%; and unipedal stance eyes open: -20% and closed: -73%, all P < .01). 1RM correlated with 6MWT (r = .45), stair climbing (r = -.44), 30sSTS (r = .43), walking efficiency (r = .26), and stance eyes open (r = .33) and closed (r = .45), all P < .01. Rapid force development correlated with 6MWT (r = .54), stair climbing (r = -.49), 30sSTS (r = .45), walking efficiency (r = .26), and stance eyes open (r = .44) and closed (r = .51), all P < .01. In conclusion, skeletal muscle FGC and functional performance are reduced in patients with schizophrenia and should be recognized as important aspects of the patient groups' impaired health. Resistance training aiming to improve these components should be considered an important part of clinical treatment.

A comprehensive cardiovascular disease risk profile in patients with schizophrenia.

Patients with schizophrenia are physically inactive and have high prevalence of cardiovascular disease (CVD). Peak oxygen uptake (V̇O2peak ) is one of the strongest predictors for CVD, yet is rarely investigated in this patient population, and how V̇O2peak relates to other conventional CVD risk measures in this population is unclear. We measured treadmill V̇O2peak along with daily physical activity assessed by triaxial accelerometry, body mass index (BMI), waist circumference, blood pressure, lipid profiles, and glucose in 48 outpatients (28 men, 35 ± 10 (SD) years; 20 women, 35 ± 12 years), diagnosed with schizophrenia, schizotypal, or delusional disorders (ICD-10; F20-29). The patients were compared with 48 age- and sex-matched healthy references (±2 years) and normative data from the population. V̇O2peak was 34.5 ± 8.7 mL/kg/min (men) and 26.4 ± 7.0 mL/kg/min (women), which was 27% and 30% lower than healthy references, respectively (both P < 0.01). V̇O2peak was not associated with daily physical activity in men while a weak association was seen in women (steps per day: r2  = 0.26; counts per minute: r2  = 0.25; P < 0.05). BMI (26.0 ± 6.1 kg/m2 ) revealed that patients were moderately overweight with a waist circumference of 103 ± 17 cm. Lipid- and glucose levels, and blood pressure were all within normative range. Our data advocate the utilization of V̇O2peak assessment for CVD risk profile determination in patients with schizophrenia. Daily physical activity was poorly and inconsistently related to V̇O2peak, suggesting increased daily physical activity might not translate into improved V̇O2peak and CVD risk reduction.

Functional Performance With Age: The Role of Long-Term Strength Training.

BACKGROUND AND PURPOSE: Physical function is shown to decline with age. However, how long-term strength training may attenuate the age-related limitation in functional tasks with various force demands is unclear. METHODS: In a cross-sectional study, we assessed maximal muscle strength, initial and late phase rate of force development (RFD), as well as 4 tests of functional performance in 11 strength-trained master athletes (MAs), 11 recreationally active older adults (AEs), 10 sedentary older adults (SOAs), and 9 moderately active young controls. Functional performance was divided into 2 categories: more force-demanding (chair-rising ability and stair-climbing power) and less force-demanding (habitual walking speed and 1-leg standing) tasks. RESULTS: MA exhibited 75%, 45%, and 26% higher leg press maximal strength compared with SOA, AE, and young, respectively (P < .01). MA leg press RFD was not different from young, but was higher compared to AE and SOA during both the initial (0-50 ms: 104%-177%, P < .05) and late phase (100-200 ms: 37%-52%, P < .05) of muscle contraction. MA also showed better mean (SD) performance compared with AE and SOA (P < .05) in more force-demanding functional tasks; chair-rising ability (MA: 6.2 (1.2) seconds; AE: 8.6 (1.8) seconds; SOA: 9.7 (3.0) seconds; young: 6.5 (1.0) seconds) and stair-climbing power (MA: 701 (161) W; AE: 556 (104) W; SOA: 495 (116) W; young: 878 (126) W). No differences (mean (SD)) were observed between MA and AE in less force-demanding tasks, but both groups were superior (P < .05) compared with SOA in walking speed (MA: 1.49 (0.21) m·s; AE: 1.56 (0.17) m·s; SOA: 1.27 (0.22) m·s; young: 1.62 (0.22) m·s) and balance test completion (MA: 45%; AE: 45%; SOA: 0%; young: 100%). CONCLUSION: Our results reveal that maintaining a high muscle force-generating capacity into older age is related to beneficial effects on functional performance, which may not be achieved with recreational activity, thus highlighting strength training as an important contribution to healthy aging.

Lifelong strength training mitigates the age-related decline in efferent drive.

Recently, we documented age-related attenuation of efferent drive to contracting skeletal muscle. It remains elusive if this indication of reduced muscle strength is present with lifelong strength training. For this purpose, we examined evoked potentials in the calf muscles of 11 [71 ± 4 (SD) yr] strength-trained master athletes (MA) contrasted with 10 (71 ± 4 yr) sedentary (SO) and 11 (73 ± 6 yr) recreationally active (AO) old subjects, as well as 9 (22 ± 2 yr) young controls. As expected, MA had higher leg press maximal strength (MA, 185 ± 32 kg; AO, 128 ± 15 kg; SO, 106 ± 11 kg; young, 147 ± 22 kg, P < 0.01) and rate of force development (MA, 5,588 ± 2,488 N/s; AO, 2,156 ± 1,100 N/s; SO, 2,011 ± 825 N/s; young, 3,663 ± 1,140 N/s, P < 0.05) than the other groups. MA also exhibited higher musculus soleus normalized V waves during maximal voluntary contractions (MVC) [maximal V wave amplitude/maximal M wave during MVC (Vsup/Msup); 0.28 ± 0.15] than AO (0.13 ± 0.06, P < 0.01) and SO (0.11 ± 0.05, P < 0.01), yet lower than young (0.45 ± 0.12, P < 0.01). No differences were apparent between the old groups in H reflex recorded at rest or during MVC [maximal H reflex amplitude/maximal M wave during rest (Hmax/Mmax); maximal H reflex amplitude during MVC/maximal M wave during MVC (Hsup/Msup)], and all were lower (P < 0.01) than young. MA (34.4 ± 2.1 ms) had shorter (P < 0.05) H reflex latency compared with AO (36.4 ± 3.7 ms) and SO (37.3 ± 3.2 ms), but longer (P < 0.01) than young (30.7 ± 2.0 ms). Using interpolated twitch analysis, MA (89 ± 7%) had plantar flexion voluntary activation similar to young (90 ± 6%), and this was higher (P < 0.05), or tended to be higher (P = 0.06-0.09), than SO (83 ± 10%) and AO (84 ± 5%). These observations suggest that lifelong strength training has a protective effect against age-related attenuation of efferent drive. In contrast, no beneficial effect seems to derive from habitual recreational activity, indicating that strength training may be particularly beneficial for counteracting age-related loss of neuromuscular function.