• Change of isokinetic back muscle strength [ Time Frame: Baseline, 24 months, and 48 months ]
  Isokinetic back extensor strength using Biodex
• Lumbar paraspinal muscle quantity and quality [ Time Frame: Baseline ]
  Lumbar paraspinal muscle examination using L-S spine MRI

• Change of back extensor strength [ Time Frame: Baseline, 12 months, and 24 months ]
  Isokinetic back extensor strengh using Biodex
• Change of spinal sagittal balance [ Time Frame: Baseline, 12 months, and 24 months ]
  Spinopelvic parameters using simple whole spine X-ray
• Lumbar paraspinal muscle quantity and quality [ Time Frame: Baseline ]
  Lumbar paraspinal muscle examination using L-S spine MRI

• Change of appendicular limb mass [ Time Frame: Baseline, 24 months, and 48 months ]
  Appendicular limb mass measure using wholebody DEXA and BIA
• Change of short physical performance battery [ Time Frame: Baseline, 24 months, and 48 months ]
  Physical performance measure by walking speed, balance test, and chair standing
• Laboratory test with biomarker [ Time Frame: Baseline, 24 months, and 48 months ]
  Serum IL-6 level
• Change of spinal sagittal balance [ Time Frame: Baseline, 24 months, and 48 months ]
  Spinopelvic parameters using simple whole spine X-ray
• Change of back performance scale [ Time Frame: Baseline, 24 months, and 48 months ]
  Sock Test, the Pick-up Test, the Roll-up Test, the Fingertip-to-Floor Test, and the Lift Test.

• Change of appendicular limb mass [ Time Frame: Baseline, 12 months, and 24 months ]
  Appendicular limb mass meausure using wholebody DEXA and BIA
• Change of short physical performance battery [ Time Frame: Baseline, 12 months, and 24 months ]
  Physical performance measure by walking speed, balance test, and chair standing
• Laboratory test with biomarker [ Time Frame: Baseline ]
  Serum IL-6 level

Sarcopenia on lumbar paraspinal muscles is receiving renewed attention as a cause of spinal degeneration. However, there are few studies on the precise concept and diagnostic criteria for spinal sarcopenia. Here, we develop the concept of spinal sarcopenia in community-dwelling healthy elderly people. In addition, we aim to observe the natural aging course of paraspinal muscle and back muscle strength, and investigate the association between conventional sarcopenic indices and spinal sarcopenia.

This is a prospective observational cohort study with 120 healthy community-dwelling elderly people for 4 years. All subjects will be recruited according to no sarcopenia, possible sarcopenia, sarcopenia, and severe sarcopenia groups. The primary outcomes of this study are isokinetic back muscle strength and lumbar paraspinal muscle quantity and quality using lumbar spine MRI. Conventional sarcopenic indices and spine specific outcomes such as spinal sagittal balance, back performance scale, and Sorenson test will be also assessed. The data will be analysed using the intention-to-treat principle.

This is a prospective observational cohort study with 120 healthy community-dwelling elderly people in a single center (SMG-SNU Boramae Medical Center). Individual follow-up will last 4 years. Elderly people (≥ 65 years old) who are community-dwellers and able to walk with or without assistive devices) will be included. Sarcopenia can be divided by two stages: 1) possible sarcopenia (PS) defined by low handgrip strength and/or low gait speed and 2) sarcopenia (SA) confirmed by low handgrip strength and/or low gait speed and low muscle mass by the consensus report of the Asian working group for sarcopenia. No sarcopenia (NS) group is added to this classification, and the study participants are classified into three groups (NS, PS, and SA) after the screening tests. All outcome variables will be collected at baseline, 2 and 4 years. However, L-S spine MRI for lumbar paraspinal muscle quantity and quality will be performed only at baseline.

Data will be collected using a standardised data entry form and entered into the data management system. The intention-to-treat principle will be used for data analysis. Participant characteristics will be described using means and standard deviations for continuous data and frequencies and percentages for categorical data. The three groups will be compared using an analysis of variance (ANOVA) or the non-parametric equivalence Kruskal-Wallis test if required. To compare paired data (intra-group) between two different points, we will use repeated-measures ANOVA and Friedman tests for continuous and non-parametric data, respectively.

• Sarcopenia
• Spinal Disease

Inclusion Criteria:

1. Elderly people aged 65 and over;
2. Community dweller;
3. Ambulator with or without an assistive device.

Exclusion Criteria:

1. low back pain with moderate severity (numeric rating scale 5 and over);
2. history of any types of lumbar spine surgery;
3. history of hip fracture surgery and arthroplasty of hip or knee;
4. contraindications for MRI (such as cardiac pacemaker, implanted metallic objects, and claustrophobia);
5. disorders in central nervous system (such as stroke, parkinsonism, spinal cord injury);
6. cognitive dysfunction (Mini Mental State Examination score < 24);
7. communication disorder (such as severe hearing loss);
8. severe cardiopulmonary disease (such as heart failure with New York Heart Association Class III or IV);
9. uncontrolled chronic disease (such as hypertension with systolic blood pressure >165 and diastolic blood pressure >95);
10. musculoskeletal condition affecting physical function (such as amputation of limb);
11. long term use of corticosteroids due to inflammatory disease;
12. malignancy requiring treatment within 5 years; and
13. other medical conditions which needs active treatment; patients who refuse to participate in a study will also be excluded.